Pinned tabs can be closed accidentally
According to he description of “pinned tabs” (https://support.mozilla.org/en-US/kb/pinned-tabs-keep-favorite-websites-open):
“Pinned Tabs are small, can't be closed accidentally and open automatically when you start Firefox.”
Unfortunately, this is no true. Often, I find that my pinned tabs end up moved to another window. I cannot say why it happens, but it certainly does, and often. I suspect it is related to dragging the mouse when I am trying to click. I am disabled, and sometimes my attempt to click results in some dragging. If you drag a pinned tab off the left edge of the window, it moves the pinned tab to a new window and unpins the tab. At this point, it is quite easy to accidentally close the tab, and the tab will no longer be automatically opened when Firefox is started.
It should not be so easy to drag a pinned tab to a new window. This behavior should be changed.
There is a pref to disable the tear off feature, so you can try to toggle this pref to see if that works for you.
- browser.tabs.allowTabDetach = false
You can open the about:config page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue.
Unfortunately, that disables any dragging of a tab to a new window, which is a feature I use regularly. Perhaps we need a browser.tabs.allowpinnedTabDetach.
But I will keep that setting set to false for a while, in order to see whether it is what causes my tab to move to a new window. I'll let you know.
The other way to move a tab is the slower method of:
- select multiple tabs if desired
- right-click the tab to move to a new window
- click Move Tab(s) and then Move to New Window
But that doesn't allow drag and drop directly to the tabs bar of a different window.