The "drag doesn't work outside widget boundaries" seems to be a mix of Nuklear-specific and platform-specific problems.
It seems that scrollbars don't loose input when the mouse is not over them, but slider widgets do (that would be a Nuklear specific problem).
For the problem that an app might lose mouse input when the mouse moves outside the window boundary, this must be handled differently depending on the underlying OS. For instance on Windows you need to call SetCapture() [1]. The platform integration isn't handled by Nuklear itself, so you'll see different problems like this pop up depending on how carefully the platform integration has been implemented (the official samples should be in better shape though I guess).
It seems that scrollbars don't loose input when the mouse is not over them, but slider widgets do (that would be a Nuklear specific problem).
For the problem that an app might lose mouse input when the mouse moves outside the window boundary, this must be handled differently depending on the underlying OS. For instance on Windows you need to call SetCapture() [1]. The platform integration isn't handled by Nuklear itself, so you'll see different problems like this pop up depending on how carefully the platform integration has been implemented (the official samples should be in better shape though I guess).
[1] https://docs.microsoft.com/en-us/windows/win32/api/winuser/n...