alt-enter maddness

Hi, when I edit scala code in my projects, occasionally I need to import a class (not the one where the cursor is), so there is this functionality that after a bit intellij underlines unimported classes and I can press ant-enter and then get the option to import them. But it is so flaky that a lot of the time it is unhelpful. I.e. the to-be-imported class underline disappears quickly and by the time I press alt-enter it is gone . This is a very useful thing to have, is there something that can be done about this?