Joining limit reached: join & try again
Only a certain number of words can be lemmatised in one operation. If you reach the limit and get this message,
1. lemmatise by pressing F4,
2. place the highlight on the head entry again
3. press F5 and carry on lemmatising by pressing F5 on each entry you wish to attach to the head entry
4. when you've done, press F4 to join them up.