Re: FVWM: Possible bug: Jumping pointer in Darktable

Dan, thanks for helping me here.  I have to admit: I'm confused.

Dan Espen (2018-Nov-07, excerpt):
> >> You might want run "xev" and press mouse 1.
[...]
> The part I was after is this:
>
> ButtonRelease event, serial 33, synthetic NO, window 0x1200001,
>     root 0x1cf, subw 0x0, time 3086503, (119,138), root:(766,139),
>     state 0x100, button 1, same_screen YES
>           ^^^^^
[...]

So we both agree that xev thinks the Window key is *not* held down
(which is a correct observation), since otherwise the state would
contain 0x40.  Right?

> I did this:
>
> FvwmCommand 'mouse 1 A 4 Beep'
>
> Then I used xev to capture the press with the "Windows" key held down:
>
> ButtonRelease event, serial 36, synthetic NO, window 0x2e00001,
>     root 0x24d, subw 0x0, time 1095056384, (125,80), root:(1539,1094),
>     state 0x140, button 1, same_screen YES
>           ^^^^^
[...]

Yes, I observe the same, and the beep occurs where it should.  I've
also noted that the `ButtonPress` event, which should have occurred
just prior to this `ButtonRelease` is not listed by xev anymore,
because it is captured by FVWM to make the Beep.

I've verified that the jumping effect also persists with the binding
to `Beep`.  And pushing this further, also when binding to `nop`, the
no-operation.  I.e., *all* of the following lines exhibit the error:

    $ FvwmCommand 'mouse 1 A 4 Beep'        # beep
    $ FvwmCommand 'mouse 1 A 4 moveOrRaise' # bind
    $ FvwmCommand 'mouse 1 A 4 nop'         # no-op

And only if there is *no* binding, i.e., after

    $ FvwmCommand 'mouse 1 A 4'

the error does not occur.  So it is related to having the binding, not
to what the binding refers to.  But anyways, since you've asked:

    AddToFunc moveOrRaise
    + C raise
    + M move

> So, I'm unclear why Fvwm is reacting to mouse 1 on your system
> as if modifier 4 is active.
[...]

That's what I don't understand: What is it that makes you say FVWM
would act as if mod4 (linked to my Windows key) is active when
pressing Button 1?  Note that, when interacting with darktable, I do
*not* hold down the Windows key.

I can imagine that your statement comes from the reasonable assumption
that any binding to `mouse 1 A 4` could only have an effect if FVWM
sees mod4.  Maybe that binding to `mouse 1 A 4` triggers a bug that
manifests only later, in a pretty funny way, and only with Darktable?