I have a document that is 8X12 with a white background.
1. create new layer
2. click on color from swatches.
3. draw a rectangle holding shift. Now I have rectangle that has a color. (Change to Pixels in options)
Can I copy that new rectangle with a different color??
Can I copy and replace that color??
Sounds simple. I can't find a method to do it!
The reason to do it this way is the rectangle will show in layer as a colored square on transparent background.
once its been rsterised into pixels its just another image element, youd be better to keep it as a 'shape' layer and adjust the colour.
but if you need it rasterised for other purposes, then using the arrow tool (V) you can hold the alt key and click/drag the rectangle to create an additional one on the same layer, or you can copy the layer (apple + J / Ctrl+J) then use hue and saturation colourize option selected to change the colour.