Preview window empty with webkitgtk-2.42.0

[z1atk0]

When running with the newly released webkitgtk-2.42.0, the preview window appears to be empty. The darker grey header bar is still there (the mouse pointer changes to its "clickable" icon when hovering above it, and clicking it actually works), but it is invisible. When grabbing the text area with the mouse and starting to drag, the text (but not the image) becomes visible in the drag-and-drop "blob", but remains invisible in its actual window part or frame (not sure about the proper GTK terminology).

Recompiling against webkitgtk-2.42.0 does not fix the problem. It still also works fine when running with the earlier webkitgtk-2.40.5, though. So it doesn't seem to matter which webkitgtk version liferea is compiled against, but which version it is running with.

Screenshot running with webkitgtk-2.40.5:

Screenshot running with webkitgtk-2.42.0:

[lwindolf]

That's odd. Why should Webkitgtk 2.42 refuse to render what earlier version did render?

Can you please start Liferea from the CLI with --debug-html and select "Inspect" from the preview context menu to start the web developer tools. Once there check the "Console" for any errors.

Also please have a look for any terminal error output.

[z1atk0]

Well, this is what my "Inspect" Window looks like: :thinking: :man_shrugging: Looks like the same problem as with the preview window itself: if I hover around with the mouse, the cursor changes from the pointer arrow to the text selection cursor at various spots, and if I hold the left mouse button and move around (as if I wanted to select some regions), various UI elements pop up (and vanish again if I let go of the LMB). So it seems that everything is actually there, but for some reason everything is invisible.

Here's the terminal output from running liferea --debug-html 2>&1 &> liferea--debug-html.log, there's a bunch of HTML parsing errors, but I don't know if those are related to the problem at hand: liferea--debug-html.log.gz

[bbhtt]

Are you using a NVIDIA GPU by any chance? Does WEBKIT_DISABLE_COMPOSITING_MODE=1 liferea work?

[z1atk0]

Are you using a NVIDIA GPU by any chance? Does WEBKIT_DISABLE_COMPOSITING_MODE=1 liferea work?

Oh, wow! Yes and yes. Looks just fine now: Cool, thanks! :sunglasses: :+1:

[z1atk0]

I'm not using a desktop compositor at all, maybe that's the problem?

[zlatko@disclosure:~]$ gsettings get org.gnome.metacity compositor
'none'

Other applications using WebkitGTK as a rendering backend (like GNOME's Epiphany, for example) work fine, though. Hm.

[bbhtt]

Oh, wow! Yes and yes. Looks just fine now...

It's possibly this webkit2gtk bug in 2.42.0 https://bugs.webkit.org/show_bug.cgi?id=228268 that affects NVIDIA users. I suggest opening an issue there or asking in the webkit2gtk Matrix room to confirm.

[z1atk0]

Oh, wow! Yes and yes. Looks just fine now...

It's possibly this webkit2gtk bug in 2.42.0 https://bugs.webkit.org/show_bug.cgi?id=228268 that affects NVIDIA users. I suggest opening an issue there or asking in the webkit2gtk Matrix room to confirm.

Thanks, I added a comment to the bug report you pointed me to. Let's see what the webkitgtk devs have to say about it. :slightly_smiling_face:

@lwindolf feel free to close this issue if there's nothing you can do about it from within liferea.

[lwindolf]

@z1atk0 Great that it is fixed for you.

@bbhtt I totally forgot about the issue with the compositor in the meantime, thanks for reminding us about it!