On Tue, Jul 5, 2016 at 8:39 AM, Stephen Berman <stephen.berman@gmx.net> wrote:

Second, when I disable the menu bar before evaluating the code with one
of the fonts that, with the menu bar enabled, results in the frame
widening, or if I start emacs with -Q -D, then there is no
frame-widening.

​Sounds like the problem somehow relates t​o the display of menus with a particular font and size and is independent of any particular package but just that certain packages stimulate the error that is likely within the menu handling code, so you might try to step through some sections of the menu display and see when the widening triggers.

Bob