When we edit an existing Filter or merge into it, the Filter List should scroll
to and select this filter after closing the filter rules window.

Created an attachment (id=7885) [details]
qF 2.6.1 prerelease 18

Works (tested in Postbox, SeaMonkey and Thunderbird) when you create a filter
for a folder that already has a filter and you select the "Merge" option from
the assistant. Merge will open the Filter Rules and after closing the window
open the Filter list, will then scroll to the edited Filter and highlight it.

Created an attachment (id=7886) [details]
qF 2.6.1 prerelease 26

This version also highlights the new filter when carrying out a manual merge
process.