Buildship: how to run task from subproject in multiproject?

Using Buildship’s “Gradle Tasks” view in Eclipse, I can run tasks from a single-project configuration by double-clicking it.

When I do the same for task in a subproject in a multi-project configuration, Gradle writes a message to the Eclipse console:

FAILURE: Build failed with an exception.

We can run the task from the commandline just fine:
$ gradle :subproject:task

Obviously the task can be found, otherwise we couldn’t run it from the commandline, nor could Buildship’s Gradle Tasks view show it.