Forgot to say it didn't happen with 4.2.7 on Fedora 20.

Oh, and I realize the screenshot is not completely obvious: the corruption is in the lower part of the image. The top 80% of the page are OK. When I scroll, the upper part changes as expected.

@Milan,

Suspect this to be duplicate of bug 58358 (bug 56932 on OS X) but before setting it such could you please check how setting different zoom levels affect the mangled text area on redraw. Also, with longer documents does scrolling become an issue on your system?

Well, it doesn't really look like the same bug since the corruption never affects the whole page, only about 5 cm at the bottom. And scrolling always works, even with relatively long documents (35 pages).

I'll try to change the zoom level next time I see it.

I see this bug quite often while working with several documents, *one of them with several windows* (Window->New window menu). This might be the explanation.

The corrupt area may well be the space where the search bar is supposed to appear. Maybe under some circumstances, when switching between windows (especially windows of the same document), the search bar is not correctly drawn, and a corrupt buffer is shown instead? I'll try to find more details if I can. Suggestions welcome...

Seen it twice in half an hour. So I tried zooming, and indeed it makes the corrupt area become normal again. But I still don't think this is the same as bug 58358, since here the corruption only affects the same bottom area, never the rest of the document.

Here's an interesting hint: when the bug appears, if I do Window->New window, the new document has a search bar visible at the bottom, which wasn't present in the original document. So the corrupt area is supposed to be that bar.

Also, it seems to happen just after using Window->New window. I don't remember whether the original or the new window, or both, were affected. I'll check that next time.

Seen it again. I can confirm that opening the search bar and closing it fixes the bug. So that's probably the cause of the issue.

I have to set this to UNCONFIRMED as there has been no independent confirmation yet.

You could also test with 4.4.x for completeness.

Do you still encounter this rendering bug if you disable hardware acceleration in menu Tools > Options > LibreOffice > View) ?

Best regards. JBF

(In reply to Jean-Baptiste Faure from comment #9)
> Do you still encounter this rendering bug if you disable hardware
> acceleration in menu Tools > Options > LibreOffice > View) ?
Good hint. I've disabled hardware acceleration, and I've not seen the bug in ten days. Is that helpful?

(In reply to Milan Bouchet-Valat from comment #10)
> (In reply to Jean-Baptiste Faure from comment #9)
> > Do you still encounter this rendering bug if you disable hardware
> > acceleration in menu Tools > Options > LibreOffice > View) ?
> Good hint. I've disabled hardware acceleration, and I've not seen the bug in
> ten days. Is that helpful?

Yes it is.
Perhaps we should have a metabug for rendering problems which disappear when hardware acceleration is disabled. I am sure I have seen several other bug report with the same workaround.

Best regard. JBF

Actually, it's not due to hardware acceleration. I just observed it with hardware acceleration disabled on LO 4.4.2.2.

I see that from time to time. Scrolling up and down generally restores a correct view.
Setting status to NEW.

Do you have "smooth scroll" enabled in Writer options (menu Tools > Options > LibreOffice Writer > View)?

Best regards. JBF

(In reply to Jean-Baptiste Faure from comment #13)
> I see that from time to time. Scrolling up and down generally restores a
> correct view.
No, it never disappears when scrolling, even after several minutes; only opening and closing the search bar makes it go away. The issue with small corrupt areas that disappear when scrolling is a different one (that I also see from time to time).

> Setting status to NEW.
> 
> Do you have "smooth scroll" enabled in Writer options (menu Tools > Options
> > LibreOffice Writer > View)?
No, it's disabled. Should I try enabling it?

(In reply to Milan Bouchet-Valat from comment #14)
[...]
> > Do you have "smooth scroll" enabled in Writer options (menu Tools > Options
> > > LibreOffice Writer > View)?
> No, it's disabled. Should I try enabling it?

Why not? ça ne mange pas de pain ;-)

Best regards. JBF

This is years old and without steps so I set Needinfo to know if this repeats with new LO versions like 6.2.8 or 6.3.3.

FWIW I've seen it recently on 6.3, but it's quite rare so I still don't know how to reproduce.