[Ohrrpgce] SVN: teeemcee/12587 sliceedit: fix a crash where you could import over an in-memory slice tr

[subversion at HamsterRepublic.com]

teeemcee
2021-10-29 20:18:51 -0700 (Fri, 29 Oct 2021)
207
sliceedit: fix a crash where you could import over an in-memory slice tree

For example, after pressing F6 in thingbrowser, you could import a file by
pressing Enter on the "Editing thingbrowser.slice" line.
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U   wip/sliceedit.bas