Bug 170004

I agree that this should be a systemwide setting. It would increase application homogeneity and make for a tighter KDE experience.

In addition to X close buttons on tabs, a systemwide setting to enable middle-click on tabs for the purpose of closing them, similar to the Firefox web browser, would be a welcome addition. There are 'hidden settings' for some KDE applications to enable this, but not for all. For instance this will enable middle-click tab closing in Konqueror:
$ kwriteconfig --file konquerorrc --group "FMSettings" --key MouseMiddleClickClosesTab --type bool true
However, there is no similar setting for Kopete.

To summarize, this bug is asking for:
1) A central place to control tab closing behavior in the system setting application, for all KDE applications.
2) The tab closing behavior should enable / disable the X close button on tabs, and the ability to middle-click on a tab to close it.

I am changing the bug summary to better reflect the nature of this bug after discussion with the OP.

In addition to the stated behaviour options, other tab-related behaviour options would be desirable:
1) Ctrl-Tab behaviour. Default is NEXT tab. There should be an option to have this as PREVIOUS tab (similar to Alt-Tab behaviour).
2) Tab previews: whether or not mouseover a tab would pop up a preview of the tab (relevant mostly for Konqueror and Okular, should the latter adopt tabs as per Bug 155515)
3) Tab location preference. Right now, there is no homogeneity between tab locations in KDE apps. Konqueror and Dolphin: on top. Kopete: on bottom. Kate: on side.
4) A link to the Theme Colour settings, where the tab's appearance could be customized.

It is logical to assume that a user would prefer the same tab behaviour in all MDI applications. Therefore, a central place to manage such behaviour is essential to user friendliness. Implementing this feature would save the user time and frustration configuring his tabs, and provide a common face to all relevant KDE applications.

Seeing that middle click to close tab has suddenly disappeared for Konsole in 4.2 I strongly second this wish. I would suggest at least the following settings:

- Show separate New Tab / Close Tab buttons (default: on)
- Show close button on tabs (default: off)
- Close tab by middle click (default: off)
- Paste to tab by middle click (default: off)

I would also make a right click menu compulsory for tabs and this should have a way to directly access these settings.

I very much agree with comment 2's 2) & 3)

Other tab-related possibilities:

* Open new tab with double click on tab bar
* Allow tabs to be re-arranged
* Open new tab after current one
* Randomly/Deterministically colour tabs (think Firefox' ColorfulTabs)
* Show tab name, icon or name & icon (though it might make sense to allow that to be set per application)


"Open in background" should probably remain Konqueror-specific

I also feel that you should be careful not to make too many of these settings centralized because some of them might only make sense for certain applications. 

Maybe it should also be possible to select in the applications whether to use the central settings or to override them.

@Tobias: Nothing to fear about, make all possible settings centralized and if there is a usability case per-app that should not behave as user specified, then just override it on app side.
I don't see any complication there.

*** Bug 179094 has been marked as a duplicate of this bug. ***

Not sure it makes sense to centralize this, sorry. Many KDE apps today don't even have options for this anymore; the only one that does which I use is Konsole.