If you try to embed cartridges (or remove embedded cartridges) in Alpha2 (not released yet), then you wont be able to do it. The Eclipse toolign is complaining that it cannot remove an embeddable cartridge that's actually matching the application type.

Steps to reproduce
1) ASSERT: have some application running on OpenShift (ex. as1 of type jbossas-7)
2) ASSERT: double check the the OpenShift Explorer is displaying app-type (jbossas-7) as application type behind the application name and as embedded cartridge as child of the application, below the application name)
3) EXEC: in the "OpenShift Explorer" pick Edit Embeddable Cartridges... from context menu and check some cartridge (ex. switchyard)
4) EXEC: hit "Finish"

Result:
An error occurrs where the tooling tried to remove an embedded cartridge which matches the application type: