@Wingnut posted this on another thread:
Aside: Anyone else seeing forum edit-window cursor disappear… when editor preview pane is open? (firefox esr) Also saw disappearing cursor after selecting Arte’s name in line below. Re-opened preview pane… cursor came back ON in editor window. Multiple RETURNS when editing… might be problem, too. Something is weird, somewhere.
I’ve been getting the same problem - again with Firefox and it seems almost random, but I can not find any way of bringing cursor back on. I just log out, shut down my browser and start again
cheers, gryff 
