I called for more help.

Separate Security Issue: Update your Flash Player or remove it using these links; http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-windows.html Uninstall Flash Player | Windows http://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html Uninstall Flash Player | Mac

Note: Windows users should download the ActiveX for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the ActiveX.

Flash Player Version: Version 30.0.0.113

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download. <Windows Only>

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only> +++++++++++++++++++ See if there are updates for your graphics drivers https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration

What?!?! Did you READ the question???

You could only go to about:config and change browser.sessionstore.max_tabs_undo to 0. It disables the option "Undo Close Tab".

M_ichel1234 said

What?!?! Did you READ the question???

Did you read my response properly?

Hi M_ichel1234, Firefox 60 doesn't have a configuration page that allows you to disable or change built-in or add-on shortcuts. We are all hoping for such a page in a future version, but right now, I'm not aware of a way to do it.

What do you use Cmd-Shift-T for? If you have a program that can intercept that key combination before it reaches Firefox, I would think that would resolve the issue.

TyDraniu said

You could only go to about:config and change browser.sessionstore.max_tabs_undo to 0. It disables the option "Undo Close Tab".

YES! That does it. Thanks for your helpful solution!