Thanks for asking!

Currently, the only way to search annotations is to use our annotation editor(http://ugene.unipro.ru/documentation/manual/sequence_view/annotations_editor.htm...) which is under the sequence view.

If you click on an annotation in the annotation editor the sequence view will immediately select and show you the location of the annotation.

Genbank annotations are stored into groups. So, you need to find corresponding to you gene group in the annotation tree (It should be titled as "gene", other names are also possible). Then, by expanding items in the group, find an annotation which has your gene's name as its qualifier and click on it.

I've created an issue (https://ugene.unipro.ru/tracker/browse/UGENE-853) of automation of the process. It will be fixed in the next versions of UGENE.