This could be redesigned or refactored in some other way, but this is the

quickest way to silence the deprecation warnings.
There's a minor difference in that the Help button goes at the start of the

GtkCenterBox instead of just at the beginning of the actions (which would

all be on the right by default.)
Also add missing cleanup for the request dialog. This saves a couple hundred

errors from valgrind per Request Fields window from the Demo protocol.

Compiled and checked Demo protocol.