On Teams client for Windows 1.3.00.28779 as well as 1.3.00.26064 that I've been able to test, when I'm already on a call and click the share content button, I am presented with a list of thumbnails of "Desktop" screens to share as well as Windows. The list of Windows is a list of windows that were open at the time the call started, and it does not update if I open new windows or close ones that were open. It continues to list windows that were previously closed, and never seems to update to allow me to share a new document that I've opened.
If I click on one of the "ghost" windows that I have already closed but still show on the list, nothing happens. If I click on one of the windows that is still open, it shares it fine.
Clicking "Hide share options" and then clicking the share content button again does not refresh the list, it continues to be outdated. The only thing that refreshes the list is to close the meeting / call and start a new call.
I have reproduced this issue on multiple installations on different hardware with different user accounts.