Try grouping multiple sheets, then activating a different one of those
grouped/selected sheets.
You'll see that the sheet grouping stays, but the activesheet is different.
It's similar to selecting a cell and activating a cell.
If you select a range of cells (say A1:E10), then activate a cell in that
selection, the selection stays the same, but the activecell changes.
In code:
Range("a1:e10").Select
Range("c5").Activate
vs
Range("a1:e10").Select
Range("c5").Select