Add a fixed margin to a ScrollArea

[kpouer]

Hi,
I would like to have a scrollarea able to scroll in all direction but I want to add a margin with a fixed width that can only scroll vertically (just like a gutter in a text editor).
Is there a simple way to do that ?
I found a workaround with two scrollArea that are synchronized but I don't think it is very convenient.
thanks for your ideas.