I've had this problem for as long as I've had steam, and reinstalling does nothing. I can find absolutely nothing about this on Google, and no one else seems to have this issue.
When certain types of windows are open, for instance the game content conversion one, steam completely disallows me from using any other steam-related windows. For instance, if someone sends me a message, I can't respond to the message until the window is able to be closed. When trying to switch to a different window, I'll just get the generic steam error noise.
Most of the time, these windows are ones that can't be closed until an operation is complete.
i don't know why i even had the impulse ask here lol