Fix slider dragging when leaving window

[dunkmann00]

There seems to be a bug on macOS where even when the left mouse button is pressed, if you drag the cursor out of the main window, the button will read as not pressed. This will end a drag gesture, which causes unwanted behavior with the layer & gcode sliders if they are still being dragged.

This commit checks if the event is a 'leaving' event, and if so, will use the prior update call's left mouse down state. This avoids the erroneous reading and maintains the drag, if there was one.

Fixes #12879

[dunkmann00]

Before 👎

Screen.Recording.2025-02-21.at.8.18.40.PM.mov

After 👍

Screen.Recording.2025-02-21.at.8.20.11.PM.mov

[mottscanley]

This should be merged ASAP. So incredibly annoying bug and so simple fix.

[dunkmann00]

@lukasmatena Has this PR been reviewed? It would be appreciated to at least get feedback if this is something the Prusa devs are looking to fix?

[dunkmann00]

@SachCZ Is there any update on whether this PR has been looked over?

Thanks.

[adamdport]

@rtyr

[SachCZ]

As of now we do not want to merge this. In any case I have checked the code. It looks sane and it is an easy enough change. We will hopefully get back to this in the future.

[dunkmann00]

Understood. I certainly hope the team realizes this is quite an annoying bug for us macOS users. Given the linked issue is from 10 months ago combined with the wording of your last sentence, it does not instill much confidence this is the case. We will have to wait and see.

Nonetheless, thank you for providing feedback and for all the work that you put into maintaining PrusaSlicer!