Can't import domains from popup in Firefox

[jdgregson]

If a user opens the settings page from the popup in Firefox, clicking "Browse..." to select a trusted domains list to import causes the popup to close before the file selection dialog to open. Once a file is selected and the user clicks "Open", either nothing happens or they are shown a dialog stating that there has been a "catastrophic failure."

This issue is occurring on Windows 11, but probably affects other versions of Windows and other operating systems. It may be a bug in Firefox. The issue does not occur in Chrome/Chromium as the popup stays open while the file selection dialog is in use.