Moving window doesn't use accumulating MouseDelta so straying out of boundaries keeps moved window at the same spot.

imgui.cpp

@@ -2379,9 +2379,10 @@ void ImGui::NewFrame()
         IM_ASSERT(g.MovingWindow->MoveId == g.MovingWindowMoveId);
         if (g.IO.MouseDown[0])
         {
-            g.MovingWindow->RootWindow->PosFloat += g.IO.MouseDelta;
-            if (g.IO.MouseDelta.x != 0.0f || g.IO.MouseDelta.y != 0.0f)
+            ImVec2 pos = g.IO.MousePos - g.ActiveIdClickOffset;
+            if (g.MovingWindow->RootWindow->PosFloat.x != pos.x || g.MovingWindow->RootWindow->PosFloat.y != pos.y)
                 MarkIniSettingsDirty(g.MovingWindow->RootWindow);
+            g.MovingWindow->RootWindow->PosFloat = pos;
             FocusWindow(g.MovingWindow);
         }
         else
@@ -2930,6 +2931,7 @@ void ImGui::EndFrame()
                         g.MovingWindow = g.HoveredWindow;
                         g.MovingWindowMoveId = g.MovingWindow->MoveId;
                         SetActiveID(g.MovingWindowMoveId, g.HoveredRootWindow);
+                        g.ActiveIdClickOffset = g.IO.MousePos - g.MovingWindow->RootWindow->Pos;
                     }
                 }
                 else if (g.NavWindow != NULL && GetFrontMostModalRootWindow() == NULL)