I have the Save all files before build checkbox checked (as is Qt Creator's default, I believe.) This works as expected for all the build actions except for the action to build the current file, which builds the version on disk without first saving.

This is inconvenient since I mostly use the Build File action to quickly check that what I've just typed is valid code. Remembering to save first isn't a huge deal, but it is an extra step.

This is in a CMake based project, if that matters.