Add disabled tab style

editor/editor_themes.cpp

@@ -481,6 +481,10 @@ Ref<Theme> create_editor_theme(const Ref<Theme> p_theme) {
 	style_tab_unselected->set_bg_color(dark_color_1);
 	style_tab_unselected->set_border_color_all(dark_color_2);
 
+	Ref<StyleBoxFlat> style_tab_disabled = style_tab_selected->duplicate();
+	style_tab_disabled->set_bg_color(color_disabled_bg);
+	style_tab_disabled->set_border_color_all(color_disabled);
+
 	// Editor background
 	theme->set_stylebox("Background", "EditorStyles", make_flat_stylebox(background_color, default_margin_size, default_margin_size, default_margin_size, default_margin_size));
 
@@ -742,8 +746,10 @@ Ref<Theme> create_editor_theme(const Ref<Theme> p_theme) {
 	// Tabs & TabContainer
 	theme->set_stylebox("tab_fg", "TabContainer", style_tab_selected);
 	theme->set_stylebox("tab_bg", "TabContainer", style_tab_unselected);
+	theme->set_stylebox("tab_disabled", "TabContainer", style_tab_disabled);
 	theme->set_stylebox("tab_fg", "Tabs", style_tab_selected);
 	theme->set_stylebox("tab_bg", "Tabs", style_tab_unselected);
+	theme->set_stylebox("tab_disabled", "Tabs", style_tab_disabled);
 	theme->set_color("font_color_fg", "TabContainer", font_color);
 	theme->set_color("font_color_bg", "TabContainer", font_color_disabled);
 	theme->set_color("font_color_fg", "Tabs", font_color);

scene/resources/default_theme/default_theme.cpp

@@ -682,6 +682,7 @@ void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const
 
 	theme->set_stylebox("tab_fg", "TabContainer", sb_expand(make_stylebox(tab_current_png, 4, 4, 4, 1, 16, 4, 16, 4), 2, 2, 2, 2));
 	theme->set_stylebox("tab_bg", "TabContainer", sb_expand(make_stylebox(tab_behind_png, 5, 5, 5, 1, 16, 6, 16, 4), 3, 0, 3, 3));
+	theme->set_stylebox("tab_disabled", "TabContainer", sb_expand(make_stylebox(tab_disabled_png, 5, 5, 5, 1, 16, 6, 16, 4), 3, 0, 3, 3));
 	theme->set_stylebox("panel", "TabContainer", tc_sb);
 
 	theme->set_icon("increment", "TabContainer", make_icon(scroll_button_right_png));
@@ -707,6 +708,7 @@ void fill_default_theme(Ref<Theme> &theme, const Ref<Font> &default_font, const
 
 	theme->set_stylebox("tab_fg", "Tabs", sb_expand(make_stylebox(tab_current_png, 4, 3, 4, 1, 16, 3, 16, 2), 2, 2, 2, 2));
 	theme->set_stylebox("tab_bg", "Tabs", sb_expand(make_stylebox(tab_behind_png, 5, 4, 5, 1, 16, 5, 16, 2), 3, 3, 3, 3));
+	theme->set_stylebox("tab_disabled", "Tabs", sb_expand(make_stylebox(tab_disabled_png, 5, 5, 5, 1, 16, 6, 16, 4), 3, 0, 3, 3));
 	theme->set_stylebox("panel", "Tabs", tc_sb);
 	theme->set_stylebox("button_pressed", "Tabs", make_stylebox(button_pressed_png, 4, 4, 4, 4));
 	theme->set_stylebox("button", "Tabs", make_stylebox(button_normal_png, 4, 4, 4, 4));