Cursor behaviour at the edge of windows etc.

Hi,

Recently my cursor has started behaving strangely.

Usually when the cursor is over the border of a window or something resizeable it changes to arrows to let you know what you're hovering over can be resized.

Recently it is not doing this.

The cursor does change for a split second when it crosses a pixel that would usually be the boundary of the area where the cursor would change, but it is only across one row/column of pixels. Even if I slowly move the mouse over it again it will not change the cursor again.

If I move the mouse away it will again change for a split second when it hits the pixel boundary but even if I am moving 1 pixel at a time, it will not stay on the arrow cursor, it will just flash the arrows for a split second and go back to the pointer cursor.

The same applies to this text box I am writing this in. Changes for a split second.

I can still resize and drag the windows, it's just the cursor not displaying correctly.

I wonder if there is a cursor cache I should try to purge? I've tried restarting. Problem persists.

Any help or suggestions would be much appreciated.