* Specific to Windows Server 2008 R2, tested on multiple VMs on multiple hosts
* Issue not present on Windows Server 2016, Windows 10, or Windows 7
* Size of Firefox window affects performance, leading to validate RDP refresh issue.  If half the screen is Firefox vs the whole screen, the lag is lessened
* Safe Mode immediately resolves the issues
* Safe Mode with all Add-Ons re-enabled still resolves the issue
* Hardware acceleration on or off has no impact
* Downgrading to Firefox 74 resolves the issue (but this could also be because it made me a new profile)

Ever since Firefox upgraded to version 75, using it has become impossible to use via RDP on Windows Server 2008 R2. The behavior is like Firefox completely hogs down the machine, but more likely seems to be impacting the refresh rate of the RDP session. With Firefox open, mouse begins to trail and button clicks and movement stack up and execute as much as a 5 minute delay at times. I saw a similar report, but not 100% the same, here: https://support.mozilla.org/en-US/questions/1278453 Here is what I know so far... * Specific to Windows Server 2008 R2, tested on multiple VMs on multiple hosts * Issue not present on Windows Server 2016, Windows 10, or Windows 7 * Size of Firefox window affects performance, leading to validate RDP refresh issue. If half the screen is Firefox vs the whole screen, the lag is lessened * Safe Mode immediately resolves the issues * Safe Mode with all Add-Ons re-enabled still resolves the issue * Hardware acceleration on or off has no impact * Downgrading to Firefox 74 resolves the issue (but this could also be because it made me a new profile) What other details can I provide? Is there anything else I can try? Does this qualify to report a bug on bugzilla?