Bingo,
if I inspect the ProportionalSpliiterMorph (thru halos), then evaluate in
inspector:

    self setProperty: #fullDelta toValue: 0 at 0; balanceOffsets

I then get the undesired behavior...
Thanks Christoph for the starting point

Le dim. 17 nov. 2019 à 19:20, Thiede, Christoph <
Christoph.Thiede at student.hpi.uni-potsdam.de> a écrit :

> Hi, I perceived a similar issue a year ago, I'm afraid it appears to have
> been forgotten ...
>
>
> I recently found a bug in the splitter class: Each time you mouseDown a
> splitter but not mouseMove it, it moves itself by delta=1. More concretely
> I could locate this during debugging in #balanceOffsets, where self
> layoutFrame leftFraction actually gets a larger value with every click. I
> was able to fix the problem by preventing every call to #balanceOffsets,
> but that doesn't seem to be the right solution. Since then, I haven't
> missed any splitter behavior, so I don't understand the point of this
> method.
>
> Is there any reason why #fullDelta is set here?
>
>
> In every case, I think it could be a good idea to refactor #balanceOffsets
> in terms of readability :-)
>
> Best,
> Christoph
>
> ------------------------------
> *Von:* Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im
> Auftrag von Nicolas Cellier <nicolas.cellier.aka.nice at gmail.com>
> *Gesendet:* Sonntag, 17. November 2019 19:11 Uhr
> *An:* The general-purpose Squeak developers list
> *Betreff:* [squeak-dev] MCSaveVersionDialog splitter broken
>
> Hi,
> here is how to reproduce:
> 1. save any package
> 2. click on the horizontal splitter (below the list of changes)
> 3. the splitter goes up once at button down, and once at button up by
> about the vertical size of the Accept/Cancel buttons
>
> I don't know where to start searching for it...
>
>
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