bug#41245: 27.0.91; Error clicking on a button in custom-mode in another window

[Robert Pluim <rpluim@gmail.com>]

>>>>> On Thu, 14 May 2020 10:53:36 -0300, Mauro Aranda <maurooaranda@gmail.com> said:

    Mauro> Trevor Spiteri <tspiteri@ieee.org> writes:
    >> 1. Run emacs -Q
    >> 2. Fill the *scratch* buffer with some text (350 characters is enough).
    >> 3. M-x customize-option-other-window abbrev-all-caps
    >> 4. C-x o (to switch back to *scratch* buffer window)
    >> 5. Click on "Toggle" button right next to "Abbrev All Caps"
    >> 
    >> The text " [ State ]: EDITED, shown value does not take effect until
    >> you set or save it.\n" (81 characters including new line) is inserted at
    >> point 298 in the scratch buffer, overwriting 29 characters in the
    >> process. 298 is also the point at which the State button is drawn in the
    >> custom buffer. The custom-mode window is also broken: the State button
    >> now appears as regular text.
    >> 

    Mauro> I think the proposed patches in Bug#40788 would solve this problem as
    Mauro> well.

Did I not commit the fix? .... No, I didnʼt, Iʼll get to it soon I
hope.

If the patch from Bug#40788 works Iʼll merge the two reports.

Robert