It should be addressed. Closing a connection and reopening another effectively disables use of the open Edit windows. It forces you to open another window and copy your queries to the new window to get that execute icon enabled.
I'm having the same problem. I notice that after using my editor tab for a specific connection, I close that connection (production) and open another one (test) I get back to my editor tab then I try to execute the same query with either F5 or F9 nothing happened. I Close Toad and reopened went to the same exercise and nothing. It toke me some time to figure it out: I have to open a new editor for each connection.
It would be great if this get fix for the next release.
This was behavior was changed between 4.5 and 4.6. You can still reuse your editor however you need to explicitly change the connection of an existing editor window that has had a connection before to another connection. This is because we want to avoid people accidentally executing a script to a connection that they were not intending when all they did was close a connection and opened a new one to another database without closing the editor.
To explicitly change the connection of the editor just click on the icon in the lower right corner of the screen and choose a new connection or right click on the document tab and choose "Change Connection".
While I do believe in protecting users from themselves up to a certain point, I think this functionality is a bad idea.
The user explicitly tells the program to switch to a different connection, and it doesn't, with no indication from the program that it is protecting you from yourself. To me, when a feature is there that is supposed to let you do something, but then doesn't do it and doesn't tell you why it didn't do it, that means that it's a bug.
It just seems to me like you're introducing what looks like a bug to users in order to protect them from themselves. At the least, perhaps make some kind of indication in the program that they need to explicitly change the connection on the editor.
I actually uninstalled Toad and looked for another tool, since I thought it was not working properly, but the others had issues that I didn't like. So finally I found this post and am happy now, but thought I would suggest a change, since clearly I'm not the only person to have thought that this was a problem (i.e. OP).
I had the same issue (after switching from Toad for MySQL 4.5 to 5.0) and was struggling to find out the root cause. I was more suspecting the windows OS, restarting the MySQL and connecting to the new DB on start up.
My Suggestion: In this scenario, user should some how (ex: on pressing F9 or when new DB connection is opened) be prompted to re-attach the editor window to the new DB connection.
Us developers have discussed this at length and I'm afraid but this behavior will not change. One person accidentally dropping a table in a production database outweighs a lot people being slightly inconvenienced.
It's still very easy to adopt a new connection to the editor either click on the icon in the lower right corner showing the connection for the current document or just right click on the tab of the document and choose change connection.