Desklet & Extension graphic issues after resume from standby

 * Cinnamon version 5.4.12
 * Distribution Mint 21
 * Graphics hardware *and* driver used: NVIDIA P4000 using the proprietary driver v525
 * 64 bit
 * Attach ~/.xsession-errors, or /var/log/syslog

Issue

Strange xlet (Desklet, Applet and Extension) behavior after resume from standby.

Since the upgrade to Mint 21, users of my desklets experiencing issues after standby. I can reproduce them on my machine.

It seems that the CSS rules of stylesheet.css of the respective xlet are not applied anymore after standby. A Cinnamon restart is needed to get rid of the issues.

Examples:

• diskspace@schorschii has always wrong text alignment after standby
• transparent-panels@germanfr: not transparent anymore after standby
• sometimes, my entire taskbar does not show any text after standby:
  

Steps to reproduce

1. send system to standby
2. resume system from standby
3. login
4. see the various issues

Expected behaviour

no graphic issues, as it was in Mint 20.x

Start by reproducing the reported sequence: standby, resume, and login, using Cinnamon 5.4.12 on Mint 21 with the stated NVIDIA driver. Compare the affected xlets' stylesheet.css behavior before and after resume, including diskspace@schorschii and transparent-panels@germanfr. Done means the desklets, panels, and taskbar retain their expected styling after resume without restarting Cinnamon.