[Firefox] Releasing mouse over a button after dragging sash causes button click

[laurenga]

Found in Firefox (v126): Using the demo at https://allotment.mulberryhousesoftware.com/

Drag the divider between allotment.tsx and allotment.module.css to the left and keep the left mouse button depressed until it's over the a file listing (such as allotment.tsx) then release the mouse.

This results in a new pane being opened for allotment.tsx

This behavior does not happen in Chrome.