steam/libcef links open file browser after altgr-left or altgr-right

[kisak-valve]

Your system information

• Steam client version (build number or date): March 22, 2017
• Distribution (e.g. Ubuntu): Gentoo, Fedora 25
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes

Please describe your issue in as much detail as possible:

I regularly use the right alt + left arrow key and occasionally right alt + right arrow key with browsers as a one-handed back and forward control. When returning to the list of topics on a community discussions page libcef using these keys, libcef does not react to links with left click mouse input until the window looses and regains focus, including using right click to bring up the context menu. It should be noted that text can be highlighted.

This issue does not occur when using the left alt + left or right arrow keys or if there is a window behind the steam client.

I have been seeing this issue for years, but didn't finish profiling it until recently. Tested with Mate, Cinnamon, and Gnome 3/wayland.

Steps for reproducing this issue:

1. Only have the steam client window open on the desktop
2. Navigate to a group discussion list
3. Navigate to a thread
4. Use right alt + left arrow key to return to the discussion list
5. Attempt to click any other link

[kisak-valve]

Retested, ~libcef no longer reacts to this key combination, thus does not enter the quirk state~.

Over analyzed my previous report and tested setting right alt to 3rd level input or the compose key. Clicking on links after right alt + left arrow results in the next url click bringing up the file browser window, then the client goes back to normal behavior.