Thanks Matt, I really like Reefmaster.

I'd like better selection tools. Lasso with Ctrl + and Shift - would be great and inverse selection. (multiple selection with Ctrl click doesn't seem to work at the moment as it only switches selection but rectangular selection does work)

Have a large track that weaves across lake and I would like to edit particular lengths of the sidescan to create a better sidescan mosaic but rectangular selection of diagonal lines is tedious.

Edit still like better selection but also found extra features within Reefmaster which are helping. :)

Hi Nut,
If you are trying to edit a sidescan swath by deleting track-points - definitely don't do that! It sounds like you found it already, but use the swath control bar at the bottom of the screen in conjunction with the segment split tool to pick out the bits you want.
There's two ways you can do it:

The first way, and the best way IMO, is to choose the sections of track you want before adding them to a mosaic. To do this, bring up the sidescan view of the track and adjust the swath control to the range you want, then add this to a mosaic using the right-click menu.
The second way is to add your entire track to a mosaic and then split the segment using the swath control and the scissor tool. You then need to delete the part of the track that you don't want. This is a little more tedious and also more resource intensive since you are adding bigger chunks of track to your mosaic.