Tray icon missing/empty/not shown correctly

[emtiu]

This is an attempt to combine/summarize multiple reports of the systray (notification area) icon being missing/empty/malformed, with a total of 9 users reporting as being affected, namely:

• 1 affected user: #849
• 4 affected users: #1098
• 1 affected user: #1152
• 3 affected users: #1236 (related: #1240)

Distributions affected (where known)

• 5 rolling-release/DIY distros, thus difficult to reproduce:
  • 3x Arch (all in #1098)
  • 1x Gentoo (https://github.com/bit-team/backintime/issues/1236#issue-1174215325)
  • 1x openSUSE Tumbleweed (#1152)
• 3 non-rolling releases:
  • 1x Ubuntu 21.10 (https://github.com/bit-team/backintime/issues/1236#issuecomment-1079060370)
  • 1x Elementary OS Loki (now obsolete, #849)
  • 1x Fedora 35 (Soon obsolete, https://github.com/bit-team/backintime/issues/1236#issuecomment-1091120110 / #1240)

Graphics/Desktop Environments (where known)

• 2 KDE:
  • 1 KDE/Plasma 5 on X11 (#1152)
  • 1 "KDE on Arch" (https://github.com/bit-team/backintime/issues/1098#issuecomment-857316902)
• 1 Budgie (https://github.com/bit-team/backintime/issues/1098#issuecomment-797061901)
• 1 no desktop environment (https://github.com/bit-team/backintime/issues/1098#issuecomment-811530185)
• 1 Elementary OS "Pantheon"/GNOME (#849)
• 1 XFCE 4 (#1236)
• 1 GNOME 40.4 on Ubuntu 21.10 (https://github.com/bit-team/backintime/issues/1236#issuecomment-1079060370)

user account for backintime job

• 3x root user (https://github.com/bit-team/backintime/issues/1098#issue-661971312 and https://github.com/bit-team/backintime/issues/1098#issuecomment-857316902 and #1240)

Useful logs

From #1098, 2 users reporting identical messages (both for root jobs):

Jul 20 10:35:01 j python[80624]: backintime (root/1): INFO: Take a new snapshot. Profile: 1 Main profile
Jul 20 10:35:01 j python[80624]: backintime (root/1): INFO: Call rsync to take the snapshot
Jul 20 10:35:01 j python[80629]: QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
Jul 20 10:35:01 j python[80629]: QPainter::begin: Paint device returned engine == 0, type: 2
Jul 20 10:35:01 j python[80629]: QWidget::render: Cannot render with an inactive painter
Jul 20 10:35:01 j python[80629]: QSystemTrayIcon::setVisible: No Icon set
Jul 20 10:35:08 j python[80624]: backintime (root/1): INFO: Save config file
Jul 20 10:35:08 j python[80624]: backintime (root/1): INFO: Save permissions

Past progress bar over systray feature (1.1.0 until 1.1.24)

Version 1.1.0 introduced a progress bar displayed over the systray icon: https://github.com/bit-team/backintime/blob/ab24e105e618b8b1f5d779e0d4713a6296ca46d3/CHANGES#L313

… but it caused trouble, as @Germar commented: https://github.com/bit-team/backintime/issues/849#issuecomment-356097028

That's a problem on how I solved the progress bar in the tray icon. It will load a different icon as soon as it prints the progress bar. Should be fixed as soon as we have a proper BiT icon which will have a progress indicator by it self. I already have an idea for that...

… as well as here: https://github.com/bit-team/backintime/issues/496#issuecomment-157172054

I couldn't reproduce the high CPU/memory usage on Kubuntu 15.10 but the progress bar doesn't show up either. That line should render a progress bar on top of the systray icon. It's a little hack I used to show progress in systray.

In the end, it was removed in 1.2.0: https://github.com/bit-team/backintime/blob/ab24e105e618b8b1f5d779e0d4713a6296ca46d3/CHANGES#L41

Current best guess: backintime cannot find icon from system theme to use

Backintime has no icon of its own (#215), so it uses the "save" icon (Icon=document-save in its .desktop file on Kubuntu) from any given Desktop Environment/theme as its main icon, both in menus and in the system tray.

It might be the case that such an icon cannot be found in certains circumstances (in order of decreasing likelihood):

• the root user doesn't have the right paths set (https://github.com/bit-team/backintime/issues/1236#issuecomment-1091120110)
• an unusual combination of theme/DE is active,
• there is no DE installed (https://github.com/bit-team/backintime/issues/1098#issuecomment-811530185)