The DoubleClickHdl()'s return value does not mean "was handled", but actually
"is there anything more to be done"; so if we actually destroy the dialog in
the aDoubleClickHdl.Call(this), we have to return 'false'.

Change-Id: I7c510e8341eb5f74703b4266f86cb1e840a2b1fd
Reviewed-on: https://gerrit.libreoffice.org/50261Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jan Holesovsky <kendy@collabora.com>