Bug 329174

I have the same issue on 3 of my computers running Plasma 5.

This is a regression in Qt which is addressed with code review request: https://codereview.qt-project.org/101845

Martin, many thanks for fixing this! This was one of few grave usability bugs in Plasma5...
(and i can confirm the above patch resolves the problem)

It would be great if you could mail packagers so they could maybe backport it?
At least i've already done so on openSUSE

> It would be great if you could mail packagers so they could maybe backport
> it?

I don't think this is an important enough change to notify the packagers about it .

Setting to RESOLVED UPSTREAM as the problem is fixed upstream in Qt and will be part of Qt 5.4.1.

*** Bug 341850 has been marked as a duplicate of this bug. ***

Looks like this bug can still be reproduced sometimes even with Qt 5.4.1

See https://bugs.kde.org/show_bug.cgi?id=345326

(In reply to Emmanuel Pescosta from comment #6)
> Looks like this bug can still be reproduced sometimes even with Qt 5.4.1

yes, code review request exists: https://codereview.qt-project.org/#/c/106729/

*** Bug 345326 has been marked as a duplicate of this bug. ***

(In reply to Martin Gräßlin from comment #7)
> yes, code review request exists:
> https://codereview.qt-project.org/#/c/106729/

Ah sorry, I thought that this patch has already been merged into Qt 5.4 (comment 6).

Thanks for fixing it, looking forward to 5.4.2 :)

I am running Qt 5.5 and klipper is still broken. I copy text, and it makes it into Klipper, but I try and paste, and nothing will paste. I select the item from Klipper's history but there is still no checkbox next to it. I have to select something else in the history list (which will show a checkbox) *then* can select what I just copied and paste it.

what checkboxes? The new ui doesn't have checkboxes? Are you using the old implementation?

I'm experiencing this bug as well under Arch linux with kde and plasma 5 and qt 5.5 (everything is up to date).
I have both the clipboard plasmoid and klipper and tried to keep both and only one of them open but the clipboard is lost after I close the application:
- I copy a text in kate
- I close kate
- I see the text in the clipboard history but I can't paste it using ctrl+v

plasma 5.5.5, qt 5.5.1 not using any clipboard facility
Copy some text in kwrite and close it.
Open another instance and paste. Nothing happens.

(In reply to Christos Gourdoupis from comment #13)
> plasma 5.5.5, qt 5.5.1 not using any clipboard facility

What do you mean by that? You are not using the clipboard applet? If yes that's expected: the task of the applet is exactly to prevent losing the copied content on application close.

Ok, I see. So I loaded the applet.
But the problem persists exactly as before.
The text is in the clipboard, but I cannot paste it.
However if there are other entries in the history, I can select another and paste it. 
And then I can select and paste the new one too.

That is the exact behavior that I originally saw - I believe with firefox. When the application closes the text is lost from the clipboard, but not from klipper, and it can be reselected if another text is chosen in klipper first.

I have a dual monitor setup and after cleaning up my xorg.conf the problem went away.
Multi-monitor support is broken in kf5 and under some conditions things break and windows start behaving erraticaly. 
At that point, strange things happen to the clipboard too, like not being able to copy from KDE apps at all. Restarting kwin_x11 --replace then brings back the original problem!
So could it be an underlying window manager issue?

btw, I am running 5.5.5 and still getting the same problems

(In reply to EMR_Kde from comment #18)
> btw, I am running 5.5.5 and still getting the same problems

with which applications do you see it? There are applications which actively clear the clipboard when closing.

(In reply to Martin Gräßlin from comment #19)
> (In reply to EMR_Kde from comment #18)
> > btw, I am running 5.5.5 and still getting the same problems
> 
> with which applications do you see it? There are applications which actively
> clear the clipboard when closing.

Yeah, I understand that there are some apps that clear the clipboard, but when they do, all entries are deleted. This is understandable. However, sometimes, and it bugs me because I cannot readily reproduce it, I copy something, and it goes into Klipper, but is not "Checkbox"able (if that's a word). I have to select something underneath it, then select the most recent for it to be copy/pasteable. Next time it happens I'll be keeping an eye at the similarities and post them here.

This happens quite frequently, possibly every time, with Firefox.  The text appears on the top in klipper, but cannot be pasted.  Choosing another line in klipper, and then selecting back, brings back the selected text.

So I guess my settings would be pertinent (consdering you've mentioned GTK/Gnome app, I've noted weird copy/paste/select/grab behavior, and it's very annoying in Eclipse).

"Save clipboard contents on Exit" (Checked)
"Prevent empty clipboard" (Checked)
"Ignore Images" (Checked)
"Ignore Selection" (Checked) - I like my double clipboard ;)
"Remove whitespace" (Checked)
"Enable MIME-based actions" (Checked?!) - I have no actions defined though.

For me the clipboard (klipper) is also seriously broken for quite a while now (qt-5.6.0, newest kde version).

Often the text appears in klipper, but cannot be pasted. Workaround: click "edit-contents" from klippper context menu, and copy the text from there.

Something wrong with the mime-type for applications which only accept text?

This is still an issue. I have to click on something else in the list, then click back. The data was copied from Firefox.