Inspecting `FileLocator desktop` hangs
Inspecting the result of FileLocator desktop makes GT hang and requires Primary-. to recover control.
It is not executing FileLocator desktop that hangs, but inspecting the result.
In a Pharo/Morphic playground, trying the same yields an error message:

Following the advice given there, I find that the inspector tries to read the directory corresponding to FileLocator desktop as a GIF image, which is what raises the error. I don't know why this attempt is made, nor if the GT inspector does the same.
I also see the hang, but for me it seems to be caused by a different issue: a morph is spawned/tried to be spawned (see below), which is only visible in Morphic. That seems to block the execution of the method for me.
Nice catch. We need an intercept of that notification.