Preview 1.2.1322 messes up code completion in MacOS 10.13.6

[dmurdoch]

This is not quite reproducible, but it has happened a few times:

If I start typing a name (e.g. "debug"), then partway through the list of completions pops up. If I'm typing very slowly, this happens after "deb". Sometimes, not always, if I continue typing because I didn't notice the popup, something weird happens: for this example, the "u" appears after "deb" in the console window, but the cursor is positioned before it. When I type the "g", it is inserted in the wrong place, so I end up with "debgu".

Once this happens once, it is easily reproducible in that session. However, I'm not sure what triggers it in the first place.

[kevinushey]

I tried briefly testing with your noted steps but unfortunately wasn't able to reproduce.

Some things worth asking:

• Does it reproduce in both the Source window and the Console pane?
• Does the issue reproduce for you in all files within that session, or only certain files?
• Does reproducibility of the issue seem to depend on the content of the files, or is it independent?
• Any possibility it could depend on which R packages are loaded in that session? (in case they're exporting symbols seen and used by the autocompletion engine -- seems unlikely that this could be the cause but worth asking anyhow)