Shape and Icon Z Index

[kjcornwell]

It would be nice to see (and edit) the Z index for a given shape or Icon.

[SebastianStehle]

You can already control that with these buttons:

But I think it will be clearer with the task #147

[kjcornwell]

I keep having issues with those buttons not behaving as desired. I will write up any bug findings but It's very difficult to troubleshoot why without knowing the actual Z-Indexes.