Hello loebe, seek if exist a new graphic driver, and check it again.

thank you

Try to set all plugins to "Ask to Activate" on the "Firefox/Tools > Add-ons > Plugins" page.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

The latest graphic drivers from Nvidia are installed. I started FF in Safe Mode, uninstalled all addons, deactivated all plugins and switched off hardware acceleration. Unfortunately the problem does still exist :( https://crash-stats.mozilla.com/report/index/8b759a87-aaa1-4c78-984a-9051d2150307

Maybe a usefull information: the problem is only there in the developer editon and does not affect the release version im using in parallel. And: If I right-click a link and "open in new tab" FF does NOT crash. The problem seems to only occure when I use the "+" button.