A while ago I found out that you can use "*" as wildcard in completion.
That would make a nice "tip of the day" or a short blog entry:
After invoking any completion (basic, smart, class name) you can for
example type "*mouse" and IDEA will filter the completions to only include
those suggestions that contain the string "mouse" (e.g. "addMouseListener").
When you accept a suggestion IDEA will of course overwrite the "*".
I am using that quite a lot recently.
The only slight drawback is that it currently does not work in completion
invoked inside JPA-QL...