Pressing Delete doesn't work with some tools

Pressing delete doesn't work when either the Path or Gradient tools are selected.

# Steps to replicate
- On a new project, draw a rectangle.
- Note that pressing delete will remove it from the canvas and layers panel.
- Select the path tool, and press delete. Nothing happens

# Questions
I'm not really sure how this happens, and I haven't tested very thoroughly to see what other combinations, if any, might also come up. Do different tools work for different kinds of layers? I'm not sure, but if I realize anything interesting I'll comment with my findings.