Desktop behavior - noob issues
 

Hi,

I have had some Linux encounters in the past few years, but only after Vista's death I became a daily user of Debian. And now I'm a bit puzzled.

I have a default installation of Jessie with LXDE and KDE. Everything should be in working order.

Things that happen:

When I power up the PC in LXDE, sometimes my taskbar and wallpaper go missing. Wallpaper flashes for a second, and then it's replaced by the default background.
It doesn't seem to make any difference if the last power off was made via LXDE or KDE, the problem is random. Is this normal?

The programs that I have installed in KDE via Synaptic are not visible in LXDE menu. Should they be?
How can I make them visible?

Otherwise I am a quite happy camper. I wish I had taken the final plunge sooner but that's just human nature. Staying in the comfort zone as long as possible.

perhaps your filesystem is corrupt? fsck it.

Otherwise package menu handles menus, for the most part. You can run it by itself to bring them up to date, otherwise when you install something that affects it, it should run (in theory). Seems like it's different now (jessie+), and it's menulibre that updates menus for a variety of wm's / de's. I don't run a desktop with menus so I guess I've fallen out of touch. I figure that if I can't remember it enough to type it on a command line, then I probably don't need to install it. Or type it via dmenu when I'm lazy.

You could check the log files. I believe that, even though Debian includes SystemD and you can use SystemD tools for viewing logs, it also stores log information in the traditional location of /var/log.

As this link points out, the tail command is useful in viewing the most recent events.

I experienced that before 5 weeks ago, when i accidentally change the permission of the current user home folder, it turns black screen. what i did was to boot in rescue mode (USB stick), login in LUKS and check the directory. problem solved.

Thank you all for your help, but I was unable to find the main reason for my problem, but I learned new things along the way.
I was successful in reproducing the problem by making a similar install to an old laptop, so maybe this is some LXDE problem, who knows...

Another problem that I've noticed is, that sometimes when I try to use the monitor settings in LXDE I get an error notification: "Unable to get monitor information!".
The only way to fix this has been to log out, log in to KDE, toggle monitor settings (KDE doesn't recognize my lcd projector by the way), and go back to LXDE. Hmmm...

xrandr is pretty good at manipulating monitor settings. (for non-nvidia gpus). Perhaps it's not installed. Lots of things are not installed by default in debian. Not that I've done it in recent history, but you can use tasksel and select a desktop install to grab "most" things you might be missing.

I recently got a new laptop, and it uses the amdgpu driver, which is NOT available in jessie, but does exist in stretch. But it's a recent enough hardware that I'm running arch on it since by documentation the hdmi audio portion of that driver isn't even implemented yet. And probably back on debian in two years when a decent driver has trickled down. Or I break down and run debian sid.