fix invalid MousePos when cursor got out of application window while dragging a imgui window

Author: dpethes

examples/fpimgui_impl_sdlgl2.pas

@@ -200,7 +200,7 @@ procedure ImGui_ImplSdlGL2_NewFrame(window: PSDL_Window);
   // Setup inputs
   // (we already got mouse wheel, keyboard keys & characters from SDL_PollEvent())
   mouseMask := SDL_GetMouseState(@mx, @my);
-  if ((SDL_GetWindowFlags(window) and SDL_WINDOW_MOUSE_FOCUS) <> 0) then
+  if ((SDL_GetWindowFlags(window) and SDL_WINDOW_INPUT_FOCUS) <> 0) then
       io^.MousePos := ImVec2Init(mx, my)   // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
   else
       io^.MousePos := ImVec2Init(-FLT_MAX, -FLT_MAX);