Hi all,
there seems to be no activeFocusControlId when a view has been detached.
The <activeWhen> expression for my handler looks like
<activeWhen>
<and>
<with variable="activeFocusControlId">
<equals value="graphicalViewer">
</equals>
</with>
<with variable="selection">
<count value="1">
</count>
<iterate>
<adapt type="MyType">
</adapt>
</iterate>
</with>
</and>
</activeWhen>
If the view is attached it works like expected.
This might be related to
https://bugs.eclipse.org/bugs/show_bug.cgi?id=212292