Same for me, on Win764. But not always.
When I look into the performance-graphs (Ctrl+Alt+Del) I do not see any clogging.
Question : When this happens, how about zooming in and out within your WebBrouwser's pages (google chrome : Ctrl+MouseWeel) : Is the zooming then there just as sluggish as the tool-resizing ? Seems yes for me.
So maybe it's related with a "kind of" Graphic card-associated memory".. ?
If yes, what is sharing this memory ( distinguishable priorities?).