Hello!

The script suggested by tylert on his post here might be particularly useful to disable touch events detection at load time and make Ext.NET work on such systems using Firefox 52+.

Specifically the script fools mobile devices not to take the "touch approach". If you modify it to apply the changes only and only when the browser matches the affected firefox versions (probably 52+), that would probably circumvent the issue for the time being!

Hope this helps!