You may already know this, but: the latest Tk (8.6.9) doesn't play well with tkinter. Python's solution seems to have been to bundle 8.6.8 with new installs. In my own projects I installed 8.6.8 to regain functionality.
I posted an answer to a related question on stackoverflow and included links:
--Geoff Sametz
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Message: 1
Date: Wed, 26 Jun 2019 10:58:21 -0700
From: Eric Pettersen <pett@cgl.ucsf.edu>
To: Neil Rzechorzek <njr48@cam.ac.uk>
Cc: "chimera-users@cgl.ucsf.edu BB" <chimera-users@cgl.ucsf.edu>
Subject: Re: [Chimera-users] Sudden Chimera issues with OSX Mojave?
Message-ID: <E66B6410-56F4-46D9-8596-C5AD33EE4C8D@cgl.ucsf.edu>
Content-Type: text/plain; charset="utf-8"
Hi Neil,
I don?t know why your systems would have started having problems in the last 48 hours. Nonetheless, I suggest you try using the daily build instead of the production release. The daily build uses a newer version of the Tk windowing toolkit that Chimera relies on to draw windows, handle scrolling, etc. and that newer version in particular has some fixes for bad scrolling behavior. If the daily build fails to remedy the problem, try using Chimera?s Help?Report a Bug to make a bug report. The bug report will include many details of your hardware and software setup that will help us investigate the problem.
?Eric
Eric Pettersen
UCSF Computer Graphics Lab
--
Dr. Geoffrey Sametz
QDH 104
Department of Chemistry and Biochemistry
University of Delaware
sametz@udel.edu(302) 831-3621