Tab bar steals keyboard focus with >10 tabs

[The-Compiler]

Reported by @ml-:

Tab setup:

• Open 9 tabs with any page (say duckduckgo.com)
• Open qutebrowser.org as the 10th tab (title of site starts with the letter q)
• Having >= 10 tabs is a requirement to reproduce this

Bindings in this example:

• bind <alt-q> :tab-prev
• bind <alt-w> :tab-next

What happens?

• pressing <alt-w> works fine since the 10th's tab title doesn't start with a w
• pressing <alt-q> jumps to the 10th tab regardless of what tab you currently are on

Full logs (didn't look at them yet): https://crashes.qutebrowser.org/view/0093e50b

Based on the "10 tabs" requirements this is probably yet another issue with TabWidget._toggle_visibility - I'm guessing showing the bar somehow steals keyboard focus? Might only be reproducible on KDE though.

cc @jgkamat

[jgkamat]

This feels somewhat related to qt mnemonics (see #3245) I'm guessing we can't reproduce it for the same reason we can't reproduce that issue (maybe kde does something to enable mnemonics). Either way, the tabbar shouldn't be stealing focus during the hide/show. Florian Bruhin writes:

…

Reported by @ml-: > Tab setup: > - Open 9 tabs with any page (say duckduckgo.com) > - Open qutebrowser.org as the 10th tab (title of site starts with the letter q) > - Having >= 10 tabs is a requirement to reproduce this > > Bindings in this example: > - `bind <alt-q> :tab-prev` > - `bind <alt-w> :tab-next` > > What happens? > - pressing `<alt-w>` works fine since the 10th's tab title doesn't start with a w > - pressing `<alt-q>` jumps to the 10th tab regardless of what tab you currently are on Full logs (didn't look at them yet): https://crashes.qutebrowser.org/view/0093e50b Based on the "10 tabs" requirements this is probably yet another issue with `TabWidget._toggle_visibility` - I'm guessing showing the bar somehow steals keyboard focus? Might only be reproducible on KDE though. cc @jgkamat

[jgkamat]

Here's the related log: 15:10:58 DEBUG modes modeman:_handle_keypress:172 got keypress in mode KeyMode.normal - delegating to <qutebrowser.keyinput.modeparsers.NormalKeyParser> 15:10:58 DEBUG keyboard basekeyparser:_debug_log:91 Got key: 0x57 / modifiers: 0x8000000 / text: '<Alt+w>' / dry_run True 15:10:58 DEBUG modes modeman:_handle_keypress:199 match: 2, forward_unbound_keys: auto, passthrough: False, is_non_alnum: True, dry_run: True --> filter: True (focused: <PyQt5.QtWidgets.QWidget object at 0x7f10847b3318>) 15:10:58 DEBUG modes modeman:_handle_keypress:172 got keypress in mode KeyMode.normal - delegating to <qutebrowser.keyinput.modeparsers.NormalKeyParser> 15:10:58 DEBUG keyboard basekeyparser:_debug_log:91 Got key: 0x57 / modifiers: 0x8000000 / text: '<Alt+w>' / dry_run False 15:10:58 DEBUG keyboard basekeyparser:_debug_log:91 Definitive match for '<Alt+w>'. 15:10:58 DEBUG keyboard basekeyparser:_debug_log:91 Clearing keystring (was: <Alt+w>). 15:10:58 DEBUG commands command:run:534 command called: tab-next 15:10:58 DEBUG commands command:run:549 Calling qutebrowser.browser.commands.CommandDispatcher.tab_next(<qutebrowser.browser.commands.CommandDispatcher>, 1) 15:10:58 DEBUG misc app:on_focus_object_changed:836 Focus object changed: <PyQt5.QtWidgets.QWidget object at 0x7f10a8574f78> 15:10:58 DEBUG modes tabbedbrowser:on_current_changed:691 Current tab changed, focusing <qutebrowser.browser.webengine.webenginetab.WebEngineTab tab_id=0 url='https://start.duckduckgo.com/'> 15:10:58 DEBUG modes tabbedbrowser:on_current_changed:699 Mode before tab change: normal (mode_on_change = normal) 15:10:58 DEBUG modes modeman:leave:307 Ignoring leave request for KeyMode.hint (reason tab changed) as we're in mode KeyMode.normal 15:10:58 DEBUG modes modeman:leave:307 Ignoring leave request for KeyMode.caret (reason tab changed) as we're in mode KeyMode.normal 15:10:58 DEBUG modes modeman:leave:307 Ignoring leave request for KeyMode.insert (reason tab changed) as we're in mode KeyMode.normal 15:10:58 DEBUG modes modeman:leave:307 Ignoring leave request for KeyMode.passthrough (reason tab changed) as we're in mode KeyMode.normal 15:10:58 DEBUG modes tabbedbrowser:on_current_changed:711 Mode after tab change: normal (mode_on_change = normal) 15:10:58 DEBUG modes modeman:_handle_keypress:199 match: 2, forward_unbound_keys: auto, passthrough: False, is_non_alnum: True, dry_run: False --> filter: True (focused: <PyQt5.QtWidgets.QWidget object at 0x7f10a8574f78>) 15:10:58 DEBUG modes modeman:_handle_keyrelease:219 filter: True 15:10:59 DEBUG modes modeman:_handle_keypress:172 got keypress in mode KeyMode.normal - delegating to <qutebrowser.keyinput.modeparsers.NormalKeyParser> 15:10:59 DEBUG keyboard basekeyparser:_debug_log:91 Got key: 0x51 / modifiers: 0x8000000 / text: '<Alt+q>' / dry_run True 15:10:59 DEBUG modes modeman:_handle_keypress:199 match: 2, forward_unbound_keys: auto, passthrough: False, is_non_alnum: True, dry_run: True --> filter: True (focused: <PyQt5.QtWidgets.QWidget object at 0x7f10a8574f78>) 15:10:59 DEBUG misc app:on_focus_object_changed:836 Focus object changed: <PyQt5.QtWidgets.QWidget object at 0x7f10847b3318> 15:10:59 DEBUG modes tabbedbrowser:on_current_changed:691 Current tab changed, focusing <qutebrowser.browser.webengine.webenginetab.WebEngineTab tab_id=13 url='http://qutebrowser.org/'> Looks to me like the focus object is correct (on the page (from the previous tab switch), but for some reason, either the keypress is not filtered (even though filter: True). I don't think this is related to the focus toggle, because ml can reproduce this with 10 tabs (while the focus hack kicks in at 11). Do you know why every keypress results in two calls to the handler (except the bad one), one with dry_run=True and one with dry_run=False? Maybe this is related to this line, which sets dry_run=True for ShortcutOverride (I'm guessing that after reaching 10 tabs, mnemonics are treated like shortcuts). However, that dosen't make much sense since we should still be filtering the key (returning true in eventFilter), so it shouldn't go to the page: https://github.com/qutebrowser/qutebrowser/blob/master/qutebrowser/keyinput/modeman.py#L349

[The-Compiler]

Seems something weird KDE does:

• https://stackoverflow.com/questions/32688153/how-to-disable-automatic-mnemonics-in-a-qt-application-on-kde
• https://bugs.kde.org/show_bug.cgi?id=337491
• https://bugs.kde.org/show_bug.cgi?id=394010

Wonder if there's some workaround.

[ml-]

Workaround (as found in the KDE bugreports)

Add

[Development]
AutoCheckAccelerators=false

to the file ~/.config/kdeglobals