Fixed uninitialized variables (wouldn't have a real effect because they'd be cleared in Begin()).

imgui_internal.h

@@ -490,9 +490,11 @@ struct ImGuiContext
         SetNextWindowSizeCond = 0;
         SetNextWindowContentSizeCond = 0;
         SetNextWindowCollapsedCond = 0;
-        SetNextWindowFocus = false;
+        SetNextWindowSizeConstraintRect = ImRect();
         SetNextWindowSizeConstraintCallback = NULL;
         SetNextWindowSizeConstraintCallbackUserData = NULL;
+        SetNextWindowSizeConstraint = false;
+        SetNextWindowFocus = false;
         SetNextTreeNodeOpenVal = false;
         SetNextTreeNodeOpenCond = 0;
 
@@ -599,6 +601,7 @@ struct IMGUI_API ImGuiDrawContext
         memset(StackSizesBackup, 0, sizeof(StackSizesBackup));
 
         IndentX = 0.0f;
+        GroupOffsetX = 0.0f;
         ColumnsOffsetX = 0.0f;
         ColumnsCurrent = 0;
         ColumnsCount = 1;