Drag and Drop: tweaked BeginDragDropSource() to remove indent. Added debug log.

imgui.cpp

@@ -13096,6 +13096,8 @@ bool ImGui::IsDragDropActive()
 void ImGui::ClearDragDrop()
 {
     ImGuiContext& g = *GImGui;
+    if (g.DragDropActive)
+        IMGUI_DEBUG_LOG_ACTIVEID("[dragdrop] ClearDragDrop()\n");
     g.DragDropActive = false;
     g.DragDropPayload.Clear();
     g.DragDropAcceptFlags = ImGuiDragDropFlags_None;
@@ -13134,7 +13136,7 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
     bool source_drag_active = false;
     ImGuiID source_id = 0;
     ImGuiID source_parent_id = 0;
-    if (!(flags & ImGuiDragDropFlags_SourceExtern))
+    if ((flags & ImGuiDragDropFlags_SourceExtern) == 0)
     {
         source_id = g.LastItemData.ID;
         if (source_id != 0)
@@ -13196,12 +13198,15 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
     }
 
     IM_ASSERT(g.DragDropWithinTarget == false); // Can't nest BeginDragDropSource() and BeginDragDropTarget()
-    if (source_drag_active)
+    if (!source_drag_active)
-    {
+        return false;
+
+    // Activate drag and drop
     if (!g.DragDropActive)
     {
         IM_ASSERT(source_id != 0);
         ClearDragDrop();
+        IMGUI_DEBUG_LOG_ACTIVEID("[dragdrop] BeginDragDropSource() DragDropActive = true, source_id = %08X\n", source_id);
         ImGuiPayload& payload = g.DragDropPayload;
         payload.SourceId = source_id;
         payload.SourceParentId = source_parent_id;
@@ -13231,8 +13236,6 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
         g.LastItemData.StatusFlags &= ~ImGuiItemStatusFlags_HoveredRect;
 
     return true;
-    }
-    return false;
 }
 
 void ImGui::EndDragDropSource()