Cannot Copy Text from Thunderbird 115.9.0 (64-bit)

<p>I am using Thunderbird 115.9.0 (64-bit) on Windows 11. </p><p>I am finding that I cannot copy text out of a Thunderbird window (e.g., an incoming message or a message-composition pane). </p><p>If I select text and "copy" (e.g., by context menu with right click or Edit-Copy ordinary menu), my clipboard is cleared. </p><p>If my clipboard is not clear (text copied from another application), I can paste that into a Thunderbird message-composition pane. But if I then select that same text in the Thunderbird window and then do "copy" (above), the clipboard is cleared. Pasting (into a Thunderbird window or something else, like Notepad) pastes nothing. </p><p>I have noticed this problem only in the last week or so. </p>