am I right with select and group?

[Tiemo Hollmann TB]

Hello all, I'm not sure if my syntax is right, because I get unwanted
results. What I want to do is to export a snapshot from two images as one
image into the clipboard. I am doing this like:

Select empty

Show img "a"

Show img "b"   

            select img "a" and img "b"

            group

            set the name of last group to "grpClipboard"

            export snapshot from grp "grpClipboard" to tClipboardImage as
PNG

            set the clipboarddata["image"] to tClipboardImage

            select empty

        if  exists(group "grpClipboard") then

            select group "grpClipboard"

            ungroup

        end if

hide image "a"

hide image "b"

select empty     

everything works fine, but from now and then another hidden group, named
"test" gets shown und ungrouped, or gets the name "grpClipboard". If it is
not a bug, I assume my syntax with select and group isn't safe. Can anyone
give me a hint, how to make this code more dafe, that always only my wanted
images are selected and grouped / ungrouped?

Thanks Tiemo