For the purpose of refreshing current errors I use make but when I do, the previous code coverage overlay (red/green on left of code) disappears. There is an option to show code coverage reports (Ctrl Alt F6) but they do not reappear when selected. This is important for those trimming down large libraries as they need to see what classes and methods are used and unused as well as a current list of errors to fix.
Use IDEA code coverage runner.
Code coverage only disappears on classes that receive errors since last build. This does not mean that they were modified but simply references were removed to clean library.