In a subdir project, any way to only build the active subproject and its dependencies?

[Guy Gizmo]

I have a subdirs project that looks like this:

TEMPLATE = subdirs

SUBDIRS += app foo bar lib

app.subdir = app
foo.subdir = foo
bar.subdir = bar
lib.subdir = lib

app.depends = lib

When the run configuration is set to app and I press Command+B (or Control+B if I'm on Windows), it will go through and run the build process for all four subprojects. And since they share a lot of source files, often there's quite a bit of compilation to do for either foo or bar. However I don't need the build results for foo or bar in order to run app, so the time spent trying to compile them, or even just analyze them to see if anything needs compiling, only delays me.

So is there any way I can have Qt Creator only build what's necessary to run whichever subproject is selected as the run configuration, when I type the keyboard shortcut to build or run?

I've found I can right-click one of the subprojects and tell just that to build, but a) that doesn't build any dependencies, and b) I haven't found any way to assign that to a keystroke.

[Guy Gizmo]

I've figured it out: the trick is to use the menu item "Build for run configuration..." and assign that the Command+B keystroke.