Selectable: With ImGuiSelectableFlags_AllowDoubleClick doesn't return true on the mouse button releas efollowing the double-click. Only first mouse release + second mouse down (double-click) returns true. Likewise for internal ButtonBehavior() with both _PressedOnClickRelease | _PressedOnDoubleClick. (#2503)

docs/CHANGELOG.txt

@@ -74,6 +74,9 @@ Other Changes:
   clear the focus again.
 - Popups: Fixed right-click from closing all popups instead of aiming at the hovered popup level
   (regression in 1.67).
+- Selectable: With ImGuiSelectableFlags_AllowDoubleClick doesn't return true on the mouse button release
+  following the double-click. Only first mouse release + second mouse down (double-click) returns true.
+  Likewise for internal ButtonBehavior() with both _PressedOnClickRelease | _PressedOnDoubleClick. (#2503)
 - GetMouseDragDelta(): also returns the delta on the mouse button released frame. (#2419)
 - GetMouseDragDelta(): verify that mouse positions are valid otherwise returns zero.
 - Inputs: Also add support for horizontal scroll with Shift+Mouse Wheel. (#2424, #1463) [@LucaRood]

imgui.cpp

@@ -3282,6 +3282,7 @@ static void ImGui::UpdateMouseInputs()
                 g.IO.MouseClickedTime[i] = g.Time;
             }
             g.IO.MouseClickedPos[i] = g.IO.MousePos;
+            g.IO.MouseDownWasDoubleClick[i] = g.IO.MouseDoubleClicked[i];
             g.IO.MouseDragMaxDistanceAbs[i] = ImVec2(0.0f, 0.0f);
             g.IO.MouseDragMaxDistanceSqr[i] = 0.0f;
         }
@@ -3293,6 +3294,8 @@ static void ImGui::UpdateMouseInputs()
             g.IO.MouseDragMaxDistanceAbs[i].x = ImMax(g.IO.MouseDragMaxDistanceAbs[i].x, delta_from_click_pos.x < 0.0f ? -delta_from_click_pos.x : delta_from_click_pos.x);
             g.IO.MouseDragMaxDistanceAbs[i].y = ImMax(g.IO.MouseDragMaxDistanceAbs[i].y, delta_from_click_pos.y < 0.0f ? -delta_from_click_pos.y : delta_from_click_pos.y);
         }
+        if (!g.IO.MouseDown[i] && !g.IO.MouseReleased[i])
+            g.IO.MouseDownWasDoubleClick[i] = false;
         if (g.IO.MouseClicked[i]) // Clicking any mouse button reactivate mouse hovering which may have been deactivated by gamepad/keyboard navigation
             g.NavDisableMouseHover = false;
     }

imgui.h

@@ -1435,7 +1435,8 @@ struct ImGuiIO
     bool        MouseClicked[5];                // Mouse button went from !Down to Down
     bool        MouseDoubleClicked[5];          // Has mouse button been double-clicked?
     bool        MouseReleased[5];               // Mouse button went from Down to !Down
-    bool        MouseDownOwned[5];              // Track if button was clicked inside a window. We don't request mouse capture from the application if click started outside ImGui bounds.
+    bool        MouseDownOwned[5];              // Track if button was clicked inside an imgui window. We don't request mouse capture from the application if click started outside ImGui bounds.
+    bool        MouseDownWasDoubleClick[5];     // Track if button down was a double-click
     float       MouseDownDuration[5];           // Duration the mouse button has been down (0.0f == just clicked)
     float       MouseDownDurationPrev[5];       // Previous time the mouse button has been down
     ImVec2      MouseDragMaxDistanceAbs[5];     // Maximum distance, absolute, on each axis, of how much mouse has traveled from the clicking point

imgui_widgets.cpp

@@ -429,6 +429,10 @@ void ImGui::BulletTextV(const char* fmt, va_list args)
 //   Frame N+6 (mouse button is released)   -             true             -               -                  true                 -
 //   Frame N+7 (mouse button is released)   -             true             -               -                  -                    -    
 //------------------------------------------------------------------------------------------------------------------------------------------------
+// Note that some combinations are supported,
+// - PressedOnDragDropHold can generally be associated with any flag.
+// - PressedOnDoubleClick can be associated by PressedOnClickRelease/PressedOnRelease, in which case the second release event won't be reported.
+//------------------------------------------------------------------------------------------------------------------------------------------------
 // The behavior of the return-value changes when ImGuiButtonFlags_Repeat is set:
 //                                         Repeat+                  Repeat+           Repeat+             Repeat+
 //                                         PressedOnClickRelease    PressedOnClick    PressedOnRelease    PressedOnDoubleClick
@@ -569,10 +573,13 @@ bool ImGui::ButtonBehavior(const ImRect& bb, ImGuiID id, bool* out_hovered, bool
             }
             else
             {
-                if (hovered && (flags & ImGuiButtonFlags_PressedOnClickRelease))
-                    if (!((flags & ImGuiButtonFlags_Repeat) && g.IO.MouseDownDurationPrev[0] >= g.IO.KeyRepeatDelay))  // Repeat mode trumps <on release>
-                        if (!g.DragDropActive)
-                            pressed = true;
+                if (hovered && (flags & ImGuiButtonFlags_PressedOnClickRelease) && !g.DragDropActive)
+                {
+                    bool is_double_click_release = (flags & ImGuiButtonFlags_PressedOnDoubleClick) && g.IO.MouseDownWasDoubleClick[0];
+                    bool is_repeating_already = (flags & ImGuiButtonFlags_Repeat) && g.IO.MouseDownDurationPrev[0] >= g.IO.KeyRepeatDelay; // Repeat mode trumps <on release>
+                    if (!is_double_click_release && !is_repeating_already)
+                        pressed = true;
+                }
                 ClearActiveID();
             }
             if (!(flags & ImGuiButtonFlags_NoNavFocus))