Dropbox can spam Explorer with SHChangeNotify while syncing many files, which may cause UI lag and high CPU usage by Explorer from constant overlay/icon updates.
This mod hooks SHChangeNotify inside Dropbox.exe only and turns it into a no-op.
Trade-off: Explorer won’t receive live overlay updates from Dropbox; press F5 (Refresh) in a folder view to see updated sync icons.
SHChangeNotify. Syncing and file I/O are unaffected, but updating the sync state indication in Explorer requires a manual refresh.