[openbox] Expand window to the available space

[Antoine]

Hello!
I'm trying to replace the maximize button with a "grow to available 
space" button. By this I mean enlarging the window as much as possible 
without overlapping any other window. For now, I used the "GrowToEdge" 
command, but it doesn't really work as expected.
If I put two small windows side by side and click my button on the first 
window, it will actually expand to the available space. But then, when I 
expand the second window, it will grow over the other window and take 
the whole screen, due to the strange behaviour of GrowToEdge when the 
windows are already overlapping.
Is there a way I can fix this?

Cheers,
Antoine