QtCreator freezes when opening a lot of files

QtCreator frequently freezes while I'm refactoring hundreds of source files. The more files I open the more unresponsive QtCreator becomes (freezes sporadically for a few seconds when opening about 30 files in a row). This also happens when closing all open files at once but then the freeze is like 10 seconds long. All source/header files are regular c+, so I guess it has something to do with code parsing?