With Compiz only, can't rollover between top pixel tow of menu items

[Matt Mayfield]

Steps to reproduce - with Marco vs. with Compiz:

1 - Move mouse cursor to top pixel line of screen
2 - Open a menu (MATE Menu, Global Menu, Indicator applets)
3 - With mouse cursor staying at the very top line of pixels, move between menus in the same panel applet

Expected behavior: with both window managers, the various menus are pulled down as the mouse moves between them.

Actual behavior: with Marco the menu works as expected, but with Compiz as WM, menus are not activated at the very top pixel of the screen.

Demonstration in less than 20 seconds here: https://photos.google.com/share/AF1QipMKpPbnBy--HoYJ1JE4JNh4Yif2nCw28lzPsZ2BzlCIqJZPN9ox7kisU-HT2El2nA/photo/AF1QipNzMI_Vd4f1jhKSo91glNwIsTKnzC1jJWvAtUzi?key=VnppSmFqN0FLQmFHX0hpYkRxZHk5SmNvS3pDSjFB

This shows the global menu, but the same behavior happens with all pulldown items in the top panel (indicator icons and traditional Gnome 2 style menus).s

[Matt Mayfield (mdmayfield)]

Errata - title: Top pixel *row* of menu items

[Matt Mayfield (mdmayfield)]

Sorry, no coffee yet this morning. This is on latest daily build of Ubuntu MATE 18.04, all packages updated 2018-03-10.

[Matt Mayfield (mdmayfield)]

Tried a couple things in CompizConfig Settings Manager -

1) Set Mate-panel to Above (always on top) in Window Rules. No change.
2) Excluded Mate-panel from decorations and shadows in Window Decoration. No change.

I also tried running an application (REAPER beta for Linux) that does not use GTK for menus and uses its own custom menu bar, and making it fullscreen using Compiz's Extra WM Actions. (This would also unredirect the application window.) That application's menu *does* respond to rollover at the top row of pixels.

It's as if Compiz is hiding mouse movement events from mate-panel on the very top pixel row of the screen, but is not for applications that are fullscreen, unredirected, and undecorated.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Matt Mayfield (mdmayfield)]

This also affects XFCE - if Compiz is installed and used as WM, the top line of pixels don't roll over on top panel items (menus specifically).

[Matt Mayfield (mdmayfield)]

After a lot of investigation, it seems this is caused by Compiz' default Edge Flipping binding to the top of the screen under Desktop Wall -> Bindings -> Edge Flipping. Changing Top to None resolves this.

[Alex ARNAUD (alexarnaud)]

Thank you Matt for the investigation. Do you consider the issue as resolved ?

Best regards,
Alex.

[Matt Mayfield (mdmayfield)]

Hi Alex,

I think so, although I would encourage the team to consider possibly having Edge Flipping in Compiz' settings be left off by default. I suppose whether this is a good move depends on how many users enable the Global Menu, vs. how many use Edge Flipping, and I have no insight into that.

Thank you!

Matt