Hard to believe I never noticed this little gem before recently. I have been working in Photoshop since version 2.0 – way before PS even had layers, let a lone all the great mind-boggling features it now sports. That is one of the things I miss about working with other people nearby ~ that “Hey! Look what I found!” interaction that leads to learning. So, everyone – Hey! Look what I found!
I do a lot of repeat patterns and while this has nothing to do with a repeat, this tip really speeds up part of the process. So let’s get started…
Say you have this little flower motif you want to scatter. You’ve got a total of three layers that make up this flower: 1. the flower outline, 2. the flower fill, and 3. the center fill.

Select all three layers…

…then, either using the fly-out menu (the little arrow at the top of the Layers Palette)

…or by going under Layers > Smart Objects > Group Into New Smart Object.

This will combine the three layers into one ~ however, this is not the same as merging layers together (you’ll find out why in a second).

Now go ahead and duplicate that layer as many times as you need to make the pattern you desire.

Now here’s the really cool part… You decide you don’t want that flower to be orange, but now what do you do? You’ve “lost” your layers….. Double click on one of the new “smart set” layers (any one will do, but you have to do it inside the icon box rather than over the title of the layer) and this dialog box will pop up:
Don’t be overly concerned about it, just click OK. What happens now, is a file opens that contains just your original flower – with all three layers!
Edit the file, layers as you wish, then simply save (don’t Save As, just save).

Return to your repeat file and viola! the changes you just made to the smart set are now reflected on every flower in your repeat file!
Pretty cool, eh? How could I not have known about this??? I can’t tell you how much easier this makes my life! Hope it is a new and joyous discover for some of you as well!
FYI ~ I have Photoshop CS2