Alt+scroll wheel zoom events leak to Chrome

parityerror · 2019-03-29 10:15:24

One of the main reasons for me for using xfce is the desktop zoom function using alt + scroll wheel. In xubuntu 18.04, there's a problem with the mouse wheel events leaking to Chrome browser when zooming in or out, so Chrome scrolls the web page up or down when I'm trying to zoom the desktop. I haven't found an option to disable this behaviour. It didn't happen with xubuntu 16.04. Is there a fix for this? I think the scroll wheel events should be blocked while pressing alt.

Thanks!

ToZ · 2019-03-29 11:34:43

Hello and welcome.

It is interesting that this doesn't happen with firefox - just chrome. Is it possible it is a chrome bug? Reading the scroll event while a modifier is down?

Spass · 2019-03-29 11:49:34

As a workaround you could change Alt to Super in the Window Manager Tweaks (xfwm4-tweaks-settings) window, third tab. But that said, Alt shouldn't work as Ctrl in Chrome, so maybe it's a bug in that browser, as ToZ said.

parityerror · 2019-03-29 12:09:03

Thanks for the replies. I am running the same version of Chrome on both 16.04 and 18.04 and on 16.04, zoom works ok (Chrome does not scroll). So it's not completely Chrome's fault, at least?

Changing the modifier to Super does not help - the problem remains the same.

EDIT: Using Shift as a modifier works, though.. I wonder what problems that causes ;-)

EDIT#2: Using Shift causes the same problem in Telegram (Alt works ok). Oh well.. :-(

EDIT#3: The same problem in Skype.

Last edited by parityerror (2019-03-29 14:27:06)

parityerror · 2019-04-11 14:18:00

So.. would it be possible to add an option to Window Manager Tweaks to keep wm from passing the scroll wheel events to apps when Alt (or other selected modifer) is down? Why _are_ the events passed to apps in the first place, if they are handled by the wm?

ToZ · 2019-04-11 15:35:42

You could create a bug report and see what the developer says.

alcornoqui · 2019-04-12 08:10:39

If I've understood the issue here, I have experienced the same with different image viewers in Xfce (currently Nomacs, but I think Ristretto and others are affected too).

When I zoom to see some detail in a picture, the scroll gesture makes the next pics appear, which is maddening sometimes.

Where would the bug belong? Xfwm?

ToZ · 2019-04-12 12:09:12

alcornoqui wrote:

Where would the bug belong? Xfwm?

Yes, I believe so since it handles the scroll zoom functionality.

wil · 2019-04-29 04:03:27

Same problem. Scroll + modifier leaks to all apps, but some apps don't respond to that modifier/scroll combination, which is why some apps appear not to be affected and why some people are chiminig in saying that it's the fault of certain apps... when it's xfwm4 that's 100% responsible because it's passing an already-handled event down to windows.

Also xfwm4 should be grabbing the event before passing it to modal dialogs / droplists / dialogs. Accessibility zoom fails when these are active... but I think this may be a problem with X11 itself and would have to be implemented via an XTEST sniffer.

Workaround: run xfwm4 in Xephyr (:1) for window management and run compiz outside it for zoom. And for the few apps that need 3D /overlay, make launchers for them that set DISPLAY=:0 environment for them.. of course they skip the pager and you have to ungrab the cursor to interact with them, but that's a hell of a lot less annoying than these zoom bugs if you actually need the zoom for accessibility.

I've also had a lot of fun using tiling WM in Xephyr, or fluxbox with it's handy tabbing... sure would be nice if xfwm4 added tabbing.

Last edited by wil (2019-04-29 04:11:03)

wil · 2019-04-29 06:08:13

Added this to xfwm4 bug 14027. The maintainers may reassign it.

https://bugzilla.xfce.org/show_bug.cgi?id=14027

parityerror · 2019-05-07 19:04:59

wil wrote:

Added this to xfwm4 bug 14027. The maintainers may reassign it.
https://bugzilla.xfce.org/show_bug.cgi?id=14027

Thank you!

CwF · 2019-05-13 02:08:32

wil wrote:

... but I think this may be a problem with X11 itself and would have to be implemented via an XTEST sniffer.

I agree, it's deep in xorg I think. I do a lot of trickery with spice, x2x, and x2vnc and I get bleed over events on a regular basis. In this tangled environment its more obvious when the pointer focus loses sync with the keyboard focus. I think this is the root of all these issues. It usually takes a click somewhere to sync again. Without the click, mouse focus and hovering actions work on a screen while the keyboard still types on another.

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#1 2019-03-29 10:15:24

Alt+scroll wheel zoom events leak to Chrome

#2 2019-03-29 11:34:43

Re: Alt+scroll wheel zoom events leak to Chrome

#3 2019-03-29 11:49:34

Re: Alt+scroll wheel zoom events leak to Chrome

#4 2019-03-29 12:09:03

Re: Alt+scroll wheel zoom events leak to Chrome

#5 2019-04-11 14:18:00

Re: Alt+scroll wheel zoom events leak to Chrome

#6 2019-04-11 15:35:42

Re: Alt+scroll wheel zoom events leak to Chrome

#7 2019-04-12 08:10:39

Re: Alt+scroll wheel zoom events leak to Chrome

#8 2019-04-12 12:09:12

Re: Alt+scroll wheel zoom events leak to Chrome

#9 2019-04-29 04:03:27

Re: Alt+scroll wheel zoom events leak to Chrome

#10 2019-04-29 06:08:13

Re: Alt+scroll wheel zoom events leak to Chrome

#11 2019-05-07 19:04:59

Re: Alt+scroll wheel zoom events leak to Chrome

#12 2019-05-13 02:08:32

Re: Alt+scroll wheel zoom events leak to Chrome

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