[Bug] UI display priority

### Problem:
Currently, z-index of increments linearly, which places it over other boxes and eventually, even the menu.

Examples:

### Expected:
Properties, pop ups, and menu should be above node and node contents.

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For now, I've set custom user css locally to specifically move menu and properties window to 999 and 1000, but this doesn't seem like a good modular solution. Is there a reason for z-index to continually increment, or is this a bug? I can work on this issue if I get a conclusive answer, I'm just not sure if I'm overlooking something that necessitates said incrementations.