Deleting an empty operand causes non-executable command

[Matthias Schoettle]

Deleting an empty operand, causes an exception in the controller, because the CompoundCommand is not executable.

[Matthias Schoettle]

Resolves #487: Calls createRemoveOperandContentsCommand in all cases.

Even when the operand is empty, this operation needs to remove the operand. Removal has to happen within this operation, because the operand removal needs to occur before removal of the fragments from the lifeline in order to have this information when the fragment is removed due to operand removal.

→ <<cset 8ddcbf5bde25>>

[Matthias Schoettle]

Merged in Issues/487-488-Message-View-Fixes (pull request #109)

refs #487, #488

Approved-by: Emmanuel Ng Cheng Hin [e-mail]

→ <<cset a85f100589f6>>