Allow tab deselection

doc/classes/TabBar.xml

@@ -229,8 +229,11 @@
 		<member name="clip_tabs" type="bool" setter="set_clip_tabs" getter="get_clip_tabs" default="true">
 			If [code]true[/code], tabs overflowing this node's width will be hidden, displaying two navigation buttons instead. Otherwise, this node's minimum size is updated so that all tabs are visible.
 		</member>
-		<member name="current_tab" type="int" setter="set_current_tab" getter="get_current_tab" default="0">
-			Select tab at index [code]tab_idx[/code].
+		<member name="current_tab" type="int" setter="set_current_tab" getter="get_current_tab" default="-1">
+			The index of the current selected tab. A value of [code]-1[/code] means that no tab is selected and can only be set when [member deselect_enabled] is [code]true[/code] or if all tabs are hidden or disabled.
+		</member>
+		<member name="deselect_enabled" type="bool" setter="set_deselect_enabled" getter="get_deselect_enabled" default="false">
+			If [code]true[/code], all tabs can be deselected so that no tab is selected. Click on the current tab to deselect it.
 		</member>
 		<member name="drag_to_rearrange_enabled" type="bool" setter="set_drag_to_rearrange_enabled" getter="get_drag_to_rearrange_enabled" default="false">
 			If [code]true[/code], tabs can be rearranged with mouse drag.

doc/classes/TabContainer.xml

@@ -181,8 +181,13 @@
 		<member name="clip_tabs" type="bool" setter="set_clip_tabs" getter="get_clip_tabs" default="true">
 			If [code]true[/code], tabs overflowing this node's width will be hidden, displaying two navigation buttons instead. Otherwise, this node's minimum size is updated so that all tabs are visible.
 		</member>
-		<member name="current_tab" type="int" setter="set_current_tab" getter="get_current_tab" default="0">
+		<member name="current_tab" type="int" setter="set_current_tab" getter="get_current_tab" default="-1">
 			The current tab index. When set, this index's [Control] node's [code]visible[/code] property is set to [code]true[/code] and all others are set to [code]false[/code].
+			A value of [code]-1[/code] means that no tab is selected.
+		</member>
+		<member name="deselect_enabled" type="bool" setter="set_deselect_enabled" getter="get_deselect_enabled" default="false">
+			If [code]true[/code], all tabs can be deselected so that no tab is selected. Click on the [member current_tab] to deselect it.
+			Only the tab header will be shown if no tabs are selected.
 		</member>
 		<member name="drag_to_rearrange_enabled" type="bool" setter="set_drag_to_rearrange_enabled" getter="get_drag_to_rearrange_enabled" default="false">
 			If [code]true[/code], tabs can be rearranged with mouse drag.

scene/gui/tab_bar.cpp

@@ -278,7 +278,11 @@ void TabBar::gui_input(const Ref<InputEvent> &p_event) {
 			}
 
 			if (found != -1) {
-				set_current_tab(found);
+				if (deselect_enabled && get_current_tab() == found) {
+					set_current_tab(-1);
+				} else {
+					set_current_tab(found);
+				}
 
 				if (mb->get_button_index() == MouseButton::RIGHT) {
 					// Right mouse button clicked.
@@ -616,8 +620,8 @@ void TabBar::set_tab_count(int p_count) {
 	if (p_count == 0) {
 		offset = 0;
 		max_drawn_tab = 0;
-		current = 0;
-		previous = 0;
+		current = -1;
+		previous = -1;
 	} else {
 		offset = MIN(offset, p_count - 1);
 		max_drawn_tab = MIN(max_drawn_tab, p_count - 1);
@@ -640,7 +644,12 @@ int TabBar::get_tab_count() const {
 }
 
 void TabBar::set_current_tab(int p_current) {
-	ERR_FAIL_INDEX(p_current, get_tab_count());
+	if (p_current == -1) {
+		// An index of -1 is only valid if deselecting is enabled or there are no valid tabs.
+		ERR_FAIL_COND_MSG(!_can_deselect(), "Cannot deselect tabs, deselection is not enabled.");
+	} else {
+		ERR_FAIL_INDEX(p_current, get_tab_count());
+	}
 
 	previous = current;
 	current = p_current;
@@ -1069,8 +1078,13 @@ void TabBar::add_tab(const String &p_str, const Ref<Texture2D> &p_icon) {
 	queue_redraw();
 	update_minimum_size();
 
-	if (tabs.size() == 1 && is_inside_tree()) {
-		emit_signal(SNAME("tab_changed"), 0);
+	if (tabs.size() == 1) {
+		if (is_inside_tree()) {
+			set_current_tab(0);
+		} else {
+			current = 0;
+			previous = -1;
+		}
 	}
 }
 
@@ -1082,8 +1096,8 @@ void TabBar::clear_tabs() {
 	tabs.clear();
 	offset = 0;
 	max_drawn_tab = 0;
-	current = 0;
-	previous = 0;
+	current = -1;
+	previous = -1;
 
 	queue_redraw();
 	update_minimum_size();
@@ -1094,34 +1108,43 @@ void TabBar::remove_tab(int p_idx) {
 	ERR_FAIL_INDEX(p_idx, tabs.size());
 	tabs.remove_at(p_idx);
 
-	bool is_tab_changing = current == p_idx && !tabs.is_empty();
+	bool is_tab_changing = current == p_idx;
 
 	if (current >= p_idx && current > 0) {
 		current--;
 	}
+	if (previous >= p_idx && previous > 0) {
+		previous--;
+	}
 
 	if (tabs.is_empty()) {
 		offset = 0;
 		max_drawn_tab = 0;
-		previous = 0;
+		current = -1;
+		previous = -1;
 	} else {
-		// Try to change to a valid tab if possible (without firing the `tab_selected` signal).
-		for (int i = current; i < tabs.size(); i++) {
-			if (!is_tab_disabled(i) && !is_tab_hidden(i)) {
-				current = i;
-				break;
-			}
-		}
-		// If nothing, try backwards.
-		if (is_tab_disabled(current) || is_tab_hidden(current)) {
-			for (int i = current - 1; i >= 0; i--) {
+		if (current != -1) {
+			// Try to change to a valid tab if possible (without firing the `tab_selected` signal).
+			for (int i = current; i < tabs.size(); i++) {
 				if (!is_tab_disabled(i) && !is_tab_hidden(i)) {
 					current = i;
 					break;
 				}
 			}
+			// If nothing, try backwards.
+			if (is_tab_disabled(current) || is_tab_hidden(current)) {
+				for (int i = current - 1; i >= 0; i--) {
+					if (!is_tab_disabled(i) && !is_tab_hidden(i)) {
+						current = i;
+						break;
+					}
+				}
+			}
+			// If still no valid tab, deselect.
+			if (is_tab_disabled(current) || is_tab_hidden(current)) {
+				current = -1;
+			}
 		}
-
 		offset = MIN(offset, tabs.size() - 1);
 		max_drawn_tab = MIN(max_drawn_tab, tabs.size() - 1);
 
@@ -1301,17 +1324,9 @@ void TabBar::_move_tab_from(TabBar *p_from_tabbar, int p_from_index, int p_to_in
 
 	if (!is_tab_disabled(p_to_index)) {
 		set_current_tab(p_to_index);
-		if (tabs.size() == 1) {
-			_update_cache();
-			queue_redraw();
-			emit_signal(SNAME("tab_changed"), 0);
-		}
 	} else {
 		_update_cache();
 		queue_redraw();
-		if (tabs.size() == 1) {
-			emit_signal(SNAME("tab_changed"), 0);
-		}
 	}
 
 	update_minimum_size();
@@ -1398,9 +1413,9 @@ void TabBar::move_tab(int p_from, int p_to) {
 
 	if (previous == p_from) {
 		previous = p_to;
-	} else if (previous > p_from && previous >= p_to) {
+	} else if (previous > p_from && previous <= p_to) {
 		previous--;
-	} else if (previous < p_from && previous <= p_to) {
+	} else if (previous < p_from && previous >= p_to) {
 		previous++;
 	}
 
@@ -1516,10 +1531,26 @@ void TabBar::_ensure_no_over_offset() {
 	}
 }
 
+bool TabBar::_can_deselect() const {
+	if (deselect_enabled) {
+		return true;
+	}
+	// All tabs must be disabled or hidden.
+	for (const Tab &tab : tabs) {
+		if (!tab.disabled && !tab.hidden) {
+			return false;
+		}
+	}
+	return true;
+}
+
 void TabBar::ensure_tab_visible(int p_idx) {
 	if (!is_inside_tree() || !buttons_visible) {
 		return;
 	}
+	if (p_idx == -1 && _can_deselect()) {
+		return;
+	}
 	ERR_FAIL_INDEX(p_idx, tabs.size());
 
 	if (tabs[p_idx].hidden || (p_idx >= offset && p_idx <= max_drawn_tab)) {
@@ -1662,6 +1693,20 @@ bool TabBar::get_select_with_rmb() const {
 	return select_with_rmb;
 }
 
+void TabBar::set_deselect_enabled(bool p_enabled) {
+	if (deselect_enabled == p_enabled) {
+		return;
+	}
+	deselect_enabled = p_enabled;
+	if (!deselect_enabled && current == -1 && !tabs.is_empty()) {
+		select_next_available();
+	}
+}
+
+bool TabBar::get_deselect_enabled() const {
+	return deselect_enabled;
+}
+
 bool TabBar::_set(const StringName &p_name, const Variant &p_value) {
 	Vector<String> components = String(p_name).split("/", true, 2);
 	if (components.size() >= 2 && components[0].begins_with("tab_") && components[0].trim_prefix("tab_").is_valid_int()) {
@@ -1766,6 +1811,8 @@ void TabBar::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_scroll_to_selected"), &TabBar::get_scroll_to_selected);
 	ClassDB::bind_method(D_METHOD("set_select_with_rmb", "enabled"), &TabBar::set_select_with_rmb);
 	ClassDB::bind_method(D_METHOD("get_select_with_rmb"), &TabBar::get_select_with_rmb);
+	ClassDB::bind_method(D_METHOD("set_deselect_enabled", "enabled"), &TabBar::set_deselect_enabled);
+	ClassDB::bind_method(D_METHOD("get_deselect_enabled"), &TabBar::get_deselect_enabled);
 	ClassDB::bind_method(D_METHOD("clear_tabs"), &TabBar::clear_tabs);
 
 	ADD_SIGNAL(MethodInfo("tab_selected", PropertyInfo(Variant::INT, "tab")));
@@ -1790,6 +1837,7 @@ void TabBar::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "tabs_rearrange_group"), "set_tabs_rearrange_group", "get_tabs_rearrange_group");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "scroll_to_selected"), "set_scroll_to_selected", "get_scroll_to_selected");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "select_with_rmb"), "set_select_with_rmb", "get_select_with_rmb");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "deselect_enabled"), "set_deselect_enabled", "get_deselect_enabled");
 
 	BIND_ENUM_CONSTANT(ALIGNMENT_LEFT);
 	BIND_ENUM_CONSTANT(ALIGNMENT_CENTER);

scene/gui/tab_bar.h

@@ -85,8 +85,8 @@ private:
 	bool buttons_visible = false;
 	bool missing_right = false;
 	Vector<Tab> tabs;
-	int current = 0;
-	int previous = 0;
+	int current = -1;
+	int previous = -1;
 	AlignmentMode tab_alignment = ALIGNMENT_LEFT;
 	bool clip_tabs = true;
 	int rb_hover = -1;
@@ -94,6 +94,7 @@ private:
 	bool tab_style_v_flip = false;
 
 	bool select_with_rmb = false;
+	bool deselect_enabled = false;
 
 	int cb_hover = -1;
 	bool cb_pressing = false;
@@ -146,6 +147,7 @@ private:
 	int get_tab_width(int p_idx) const;
 	Size2 _get_tab_icon_size(int p_idx) const;
 	void _ensure_no_over_offset();
+	bool _can_deselect() const;
 
 	void _update_hover();
 	void _update_cache(bool p_update_hover = true);
@@ -250,6 +252,9 @@ public:
 	void set_select_with_rmb(bool p_enabled);
 	bool get_select_with_rmb() const;
 
+	void set_deselect_enabled(bool p_enabled);
+	bool get_deselect_enabled() const;
+
 	void ensure_tab_visible(int p_idx);
 
 	void set_max_tab_width(int p_width);

scene/gui/tab_container.cpp

@@ -153,9 +153,9 @@ void TabContainer::_notification(int p_what) {
 		} break;
 
 		case NOTIFICATION_POST_ENTER_TREE: {
-			if (setup_current_tab >= 0) {
+			if (setup_current_tab >= -1) {
 				set_current_tab(setup_current_tab);
-				setup_current_tab = -1;
+				setup_current_tab = -2;
 			}
 		} break;
 
@@ -259,6 +259,7 @@ void TabContainer::_repaint() {
 		tab_bar->set_anchors_and_offsets_preset(PRESET_TOP_WIDE);
 	}
 
+	updating_visibility = true;
 	for (int i = 0; i < controls.size(); i++) {
 		Control *c = controls[i];
 
@@ -282,6 +283,7 @@ void TabContainer::_repaint() {
 			c->hide();
 		}
 	}
+	updating_visibility = false;
 
 	_update_margins();
 	update_minimum_size();
@@ -440,6 +442,7 @@ void TabContainer::_on_tab_hovered(int p_tab) {
 
 void TabContainer::_on_tab_changed(int p_tab) {
 	callable_mp(this, &TabContainer::_repaint).call_deferred();
+	queue_redraw();
 
 	emit_signal(SNAME("tab_changed"), p_tab);
 }
@@ -460,6 +463,43 @@ void TabContainer::_on_active_tab_rearranged(int p_tab) {
 	emit_signal(SNAME("active_tab_rearranged"), p_tab);
 }
 
+void TabContainer::_on_tab_visibility_changed(Control *p_child) {
+	if (updating_visibility) {
+		return;
+	}
+	int tab_index = get_tab_idx_from_control(p_child);
+	if (tab_index == -1) {
+		return;
+	}
+	// Only allow one tab to be visible.
+	bool made_visible = p_child->is_visible();
+	updating_visibility = true;
+
+	if (!made_visible && get_current_tab() == tab_index) {
+		if (get_deselect_enabled() || get_tab_count() == 0) {
+			// Deselect.
+			set_current_tab(-1);
+		} else if (get_tab_count() == 1) {
+			// Only tab, cannot deselect.
+			p_child->show();
+		} else {
+			// Set a different tab to be the current tab.
+			bool selected = select_next_available();
+			if (!selected) {
+				selected = select_previous_available();
+			}
+			if (!selected) {
+				// No available tabs, deselect.
+				set_current_tab(-1);
+			}
+		}
+	} else if (made_visible && get_current_tab() != tab_index) {
+		set_current_tab(tab_index);
+	}
+
+	updating_visibility = false;
+}
+
 void TabContainer::_refresh_tab_names() {
 	Vector<Control *> controls = _get_tab_controls();
 	for (int i = 0; i < controls.size(); i++) {
@@ -490,6 +530,7 @@ void TabContainer::add_child_notify(Node *p_child) {
 	}
 
 	p_child->connect("renamed", callable_mp(this, &TabContainer::_refresh_tab_names));
+	p_child->connect(SNAME("visibility_changed"), callable_mp(this, &TabContainer::_on_tab_visibility_changed).bind(c));
 
 	// TabBar won't emit the "tab_changed" signal when not inside the tree.
 	if (!is_inside_tree()) {
@@ -547,6 +588,7 @@ void TabContainer::remove_child_notify(Node *p_child) {
 
 	p_child->remove_meta("_tab_name");
 	p_child->disconnect("renamed", callable_mp(this, &TabContainer::_refresh_tab_names));
+	p_child->disconnect(SNAME("visibility_changed"), callable_mp(this, &TabContainer::_on_tab_visibility_changed));
 
 	// TabBar won't emit the "tab_changed" signal when not inside the tree.
 	if (!is_inside_tree()) {
@@ -586,6 +628,14 @@ bool TabContainer::select_next_available() {
 	return tab_bar->select_next_available();
 }
 
+void TabContainer::set_deselect_enabled(bool p_enabled) {
+	tab_bar->set_deselect_enabled(p_enabled);
+}
+
+bool TabContainer::get_deselect_enabled() const {
+	return tab_bar->get_deselect_enabled();
+}
+
 Control *TabContainer::get_tab_control(int p_idx) const {
 	Vector<Control *> controls = _get_tab_controls();
 	if (p_idx >= 0 && p_idx < controls.size()) {
@@ -950,6 +1000,8 @@ void TabContainer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("get_use_hidden_tabs_for_min_size"), &TabContainer::get_use_hidden_tabs_for_min_size);
 	ClassDB::bind_method(D_METHOD("set_tab_focus_mode", "focus_mode"), &TabContainer::set_tab_focus_mode);
 	ClassDB::bind_method(D_METHOD("get_tab_focus_mode"), &TabContainer::get_tab_focus_mode);
+	ClassDB::bind_method(D_METHOD("set_deselect_enabled", "enabled"), &TabContainer::set_deselect_enabled);
+	ClassDB::bind_method(D_METHOD("get_deselect_enabled"), &TabContainer::get_deselect_enabled);
 
 	ADD_SIGNAL(MethodInfo("active_tab_rearranged", PropertyInfo(Variant::INT, "idx_to")));
 	ADD_SIGNAL(MethodInfo("tab_changed", PropertyInfo(Variant::INT, "tab")));
@@ -969,6 +1021,7 @@ void TabContainer::_bind_methods() {
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "tabs_rearrange_group"), "set_tabs_rearrange_group", "get_tabs_rearrange_group");
 	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "use_hidden_tabs_for_min_size"), "set_use_hidden_tabs_for_min_size", "get_use_hidden_tabs_for_min_size");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "tab_focus_mode", PROPERTY_HINT_ENUM, "None,Click,All"), "set_tab_focus_mode", "get_tab_focus_mode");
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "deselect_enabled"), "set_deselect_enabled", "get_deselect_enabled");
 
 	BIND_ENUM_CONSTANT(POSITION_TOP);
 	BIND_ENUM_CONSTANT(POSITION_BOTTOM);

scene/gui/tab_container.h

@@ -56,7 +56,9 @@ private:
 	bool theme_changing = false;
 	Vector<Control *> children_removing;
 	bool drag_to_rearrange_enabled = false;
-	int setup_current_tab = -1;
+	// Set the default setup current tab to be an invalid index.
+	int setup_current_tab = -2;
+	bool updating_visibility = false;
 
 	struct ThemeCache {
 		int side_margin = 0;
@@ -108,6 +110,7 @@ private:
 	void _on_tab_selected(int p_tab);
 	void _on_tab_button_pressed(int p_tab);
 	void _on_active_tab_rearranged(int p_tab);
+	void _on_tab_visibility_changed(Control *p_child);
 
 	Variant _get_drag_data_fw(const Point2 &p_point, Control *p_from_control);
 	bool _can_drop_data_fw(const Point2 &p_point, const Variant &p_data, Control *p_from_control) const;
@@ -174,6 +177,9 @@ public:
 	bool select_previous_available();
 	bool select_next_available();
 
+	void set_deselect_enabled(bool p_enabled);
+	bool get_deselect_enabled() const;
+
 	Control *get_tab_control(int p_idx) const;
 	Control *get_current_tab_control() const;