Can NOT confirm in Windows and Linux.
Does this happen always for you or with a specific document?

Happens with any document.

Issue started with the 5.1 series. In 5.0 styles work OK, in 5.1 there is this minor nuisance of the current style name not appearing until you click.

I am on kubuntu 15.10, Intel graphics.

Tried with both the graphic drivers as distributed by Ubuntu and the most recent (in fact from git) drivers. Makes no difference.

Also tested with compositing on and off in the window manager. This makes no difference either.

The fact that things work fine in 5.0 does not mean it is a bug in LibO. May be still an issue with graphic drivers that gets triggered by something different that is going on in 5.1 wrt 5.0.

When I have the possibility, I'll try on a machine with almost identical setup, but (old) nvidia graphics.

Is it a custom style / are the invisible ones custom styles? bug 97672

Created attachment 122724 [details]
Another example

The current style has the issue, whatever it is, custom or non custom.

The screenshot in "another example" was obtained by just calling

libreoffice --writer 

and then pressing F11.

The style panel should show "Default Style" but shows only a gray bar until one clicks in the Style panel causing a rendering update.

It's about KDE. When reporting a bug, please be specific about the system.

Looks like it works after removing the KDE integration (by uninstalling "libobasis5.1-kde-integration" or "lodevbasis5.2-kde-integration").

I confirm that this is the case.

I apologize for not having mentioned KDE before. Did not think the culprit could be in KDE or the KDE integration as this worked in 5.0.

I do not know if this can be of any relevance, but I have just noticed that removing the KDE integration package also fixes the regression in bug 78924.

I almost reported this bug before noticing it here. This bug has been bothering me for about a year. It's just innocuous enough to ignore, but I'm sure it's annoying other users.  

Is this a KDE issue? 

Is this something Libre devs can remedy?

//Looks like it works after removing the KDE integration (by uninstalling "libobasis5.1-kde-integration" or "lodevbasis5.2-kde-integration").//

I can't find either of these files on my current system:

Desktop: KDE Plasma 5.5.4
Distro: Ubuntu 16.04 xenial

Using LibreOffice 5.1.1.3

Is there another package name I should be looking for?

Found it:

libreoffice-kde

Removed. Less integrated, for sure, but removal of the bug is an improvement.

(In reply to vermontpoet from comment #12)
> Found it:
> 
> libreoffice-kde
> 
> Removed. Less integrated, for sure, but removal of the bug is an improvement.

You could also have just launched with:
SAL_USE_VCLPLUGIN=gtk libreoffice
SAL_USE_VCLPLUGIN=gen libreoffice
This is experimental still: SAL_USE_VCLPLUGIN=gtk3 libreoffice

Is there a practical difference in using these commands? I'd have to edit menu entries or invoke Libre from the command line.

Also, this is indirectly related, but I notice the menu font rendering is much improved without KDE Integration. The menu fonts used with Integration looked as if they were in needing of anti-aliasing. Much easier to read now.

Libre without KDE Integration (in Plasma 5: 16.04 at least) is, I'd have to say, a considerably improved experience. Not complaining, just observing...

Unfortunately, this is true. Furthermore, KDE integration currently brings in at least another bug, i.e. bug 78924

Adding keyword 'bibisectRequest'.

*** This bug has been marked as a duplicate of bug 92380 ***

Does not seem a duplicate of that to me.

That one is a rendering problem of the preview.

This one is a problem with the KDE integration that makes the current style entry gray until clicked.

The current style now seems to appear, but the color choice is very unfortunate: white on light gray -> extremely hard to read

Is there some kind of workaround? Like somehow changing the colors?

*** This bug has been marked as a duplicate of bug 98253 ***