Confirmed on git master.

Ctrl+Q is the "Quit Application" shortcut. This works when you're in an app like System Settings. It does not work when you're in Plasma, because you probably don't want to quit Plasma! And these widget config windows aren't apps, they're just windows spawned by Plasma. So you're probably looking for the "Close Window" shortcut which is Ctrl+W. That will close them (as well 

If this works on X11, that's a funny bug! It shouldn't be working. But it's probably not worth looking into since fixing it would undoubtedly trigger more bug reports.

*** Bug 493214 has been marked as a duplicate of this bug. ***

To Nate Graham,
Not Ctrl+Q nor Ctrl+W works for me under X11 and Wayland.
I want to close window, not Plasma, even if it is bound to Plasma specific things. wtf

Like I said, it's intentional and expected that Ctrl+Q doesn't close individual windows. Ctrl+W and Alt+F4 do this.

However I do see now that Ctrl+W isn't working here. We can make the bug report be about that.

Also, same goes with all windows which can be opened with `kcmshell6`. The full list of those is in `kcmshell6 --list`.

Just to add to the discussion, Ctrl+W is usually used by apps to close a tab, and apps that do not have any tabs open will just close instead.

For example big apps like Firefox and Chromium do this with tabs.

To add even a bit more, this is generally the world as it kinda-sorta exists:

Ctrl+Q: terminate the app and close all open windows.
Alt+F4: close the window irrespective of how many tabs it has open.
Ctrl+W: close the active tab. When the last tab is closed, or if the window has no tabs, close the window.

The only one that's really consistent is Alt+F4 which is implemented at the window manager level; Ctrl+Q and Ctrl+W need to be implemented in the app or toolkit as needed. I suppose in principle Ctrl+Q could potentially be implemented at the window manager level too, but Ctrl+W always needs to be implemented by the app or toolkit.

I'm not sure this bug makes sense as stated. There are many applications or popups that can't be closed with Ctrl+W, e.g. System Settings or the settings / about window of any application. I believe it makes sense (only?) for applications that have user-editable tabs to have such a shortcut, and I thus don't see the need to port it to applet settings, which don't have such tabs. It would also be inconsistent with other popups throught the system. 

Rather, this is how I think things should work:
- Alt+F4 for everything
- Ctrl+Q for windows
- Esc for popups

Applet settings are popups and they do close if you press "Esc", so I think the status quo currently makes sense. If not, what should be changed exactly?

Setting this to needsinfo since we're waiting on information from the reporter

I confirm that Esc does closes kcmshell6 and Applet windows. 

I suppose Ctrl+Q for Applet windows like `Desktop and Wallpapers` will improve consistency over desktop.
For example: Right-click menu in Desktop has `Desktop and Wallpapers` and `Display Configuration`. In case of `Display Configuration`, it can be closed by Ctrl+Q, but `Desktop and Wallpapers` can't be.
Esc shortcut should not be removed for Applet windows but Ctrl+Q should be added.

Niccolo got it accurate.

I set the version back to what it had been. Please don't change this. See the field descriptions here for an explanation
https://bugs.kde.org/page.cgi?id=fields.html#alias

(In reply to reports_go_brrr from comment #11)
> For example: Right-click menu in Desktop has `Desktop and Wallpapers` and
> `Display Configuration`. In case of `Display Configuration`, it can be
> closed by Ctrl+Q, but `Desktop and Wallpapers` can't be.

I confirm this inconsistent behavior on 6.3.0 and git-master

Renaming because not being closable by Ctrl+Q is intentional. That shortcut is "quit app" and that shouldn't close individual windows of Plasma. What we need to implement support for is Ctrl+W which is "close tab or window".

I started writing out a big "Codify window closing shortcuts" VDG issue, but after writing it, I concluded there isn't really anything we can do to make this significantly better, and the effort-to-reward radio is pretty poor.

These Plasma config windows are dialogs, so they already respond as normal dialogs should: to Esc and Alt+F4. We could *maybe* make windows under KDE's control with no tabs or no remaining tabs (including these) respond to Ctrl+W as well, but I believe that falls into the "effort-to-reward ratio not great" category, and we couldn't do this for non-KDE software anyway. And dialog windows responding to Ctrl+Q is definitely wrong since that's for quitting entire apps.

In other words, I think Niccolò was right. Closing again, sorry!

No need to "sorry". If not Ctrl+Q, then Ctrl+W will better than nothing in this issue.
I expect solution, not mute of it.

I'm afraid you may have to adjust your expectations. This software is provided for free, by people who are either volunteers, or paid to work on tasks their employer wants them to work on. As such, their time is spent on what they want to work on, or what the entity providing their income wants them to work on. In cases where this intersects with what you want worked on, that's great! In other cases, you'll probably have to become a volunteer and work on it yourself.

My own estimation of the effort-to-reward ratio of implementing Ctrl+W for every Qt or KDE dialog window in existence is that it's likely not very high, but I could be wrong. If you'd like to work on this, please feel free! If and when there's a patch, we can mark it as resolving this bug report. Until then, I don't think there's much sense in keeping the bug report open if it's not currently planned.

Thanks for understanding. For additional information, I'd recommend reading through https://community.kde.org/Get_Involved/Issue_Reporting#Issue_tracker_etiquette