email disappears from inbox
email messages disappear from my inbox when I click on them to open them. Happens quite a bit. The also disappear if I delete the message above them in the inbox.
Opaite Mbohovái (2)
See https://support.mozilla.org/en-US/kb/safe-mode-thunderbird Does problem go away if you start in safe mode?
I do not know what might be causing your problem - there are no recent reports of anything like this.
But I remember another case that was a mouse problem - https://bugzilla.mozilla.org/show_bug.cgi?id=524559#c13