missing repro steps or information, so very much not actionable
this seems extremely system-dependent.
do you have in-process gpu enabled? what Windows version are you on? what are GPU usage metrics at this time? are you running any other apps in the background that use GPU at all? is it that you’re normally having vsync enabled but not in windowed mode as your screen refresh rate is higher?
there’s so many questions here and yet you’re posting it as a bug report
enabling nui_useInProcessGpu seems to fixed the issue for most of the part (it still lags a bit but its not that bad and everything is usable now)
thanks for pointing it out
for anybody that wonder how they can activate it , inside Fivem client , press F8 to open Fivem console and then type : nui_useInProcessGpu true , enter, after that , it should be good to go