50% and 0.5 are the same in Keyboard Maestro, so this was not the issue.
X: SCREENVISIBLE(External,MidX)
Width: SCREENVISIBLE(External,Width)*100%
does not make sense since modern Macs do not really allow windows off the screen, and that would result in a window that had its left side in the middle of the external screen and its right side way off the right of the external screen which is not allowed.
X: SCREENVISIBLE(External,MidX)
Width: SCREENVISIBLE(External,Width)*50%
Should result in the window being on the right side of the external screen.
X: SCREENVISIBLE(External,Right)-SCREENVISIBLE(External, Width)*N%
Width: SCREENVISIBLE(External, Width)*N%
Should result it in being N% of the width and on the right side of the screen, for any given N (note that windows may have minimum sizes).
But I’m not eniterly sure where @nikivi went wrong before then or whether it was just a subtle error somewhere.
If any of the above does not work, I’d like to see a text display showing:
SCREENVISIBLE(External,Left),SCREENVISIBLE(External,MidX),SCREENVISIBLE(External,Right),SCREENVISIBLE(External,Width)