InputText: Fixed selection rectangle appearing one frame late when selecting all.

docs/CHANGELOG.txt

@@ -54,6 +54,7 @@ Other Changes:
 - InputTextMultiline: Fixed label size not being included into window contents rect unless
   the whole widget is clipped.
 - InputText: Allow activating/cancelling/validating input with gamepad nav events. (#2321, #4552)
+- InputText: Fixed selection rectangle appearing one frame late when selecting all.
 - TextUnformatted: Accept null ranges including (NULL,NULL) without asserting, in order to conform
   to common idioms (e.g. passing .data(), .data() + .size() from a null string). (#3615)
 - Disabled: Added assert guard for mismatching BeginDisabled()/EndDisabled() blocks. (#211)

imgui_widgets.cpp

@@ -4118,7 +4118,7 @@ bool ImGui::InputTextEx(const char* label, const char* hint, char* buf, int buf_
 
     // Lock the decision of whether we are going to take the path displaying the cursor or selection
     const bool render_cursor = (g.ActiveId == id) || (state && user_scroll_active);
-    bool render_selection = state && state->HasSelection() && (RENDER_SELECTION_WHEN_INACTIVE || render_cursor);
+    bool render_selection = state && (state->HasSelection() || select_all) && (RENDER_SELECTION_WHEN_INACTIVE || render_cursor);
     bool value_changed = false;
     bool enter_pressed = false;