I installed a flatpak of thunderbird on my kde neon 18.04. whenever i try to open webpage links from inside emails , thunderbird gives me an option to choose which application to use. the thing is there are no listed applications. I used kfind and typed firefox( i have it as a snap package) in it ( the location is /snap/bin/firefox). but there is no /snap directory when i browse from within the 'choose application' window within thunderbird . PLease help