Suggestion: When snap-to-grid is enabled, pasted items should snap to the grid.
Secondary suggestion: Pasted items should appear where the mouse is currently hovering, not at the last-clicked location.

I find copy & paste to be incredibly useful, but these two small improvements would be more intuitive and would dramatically speed up the rate at which I can create a map from tiled images. (The first more so than the second, but it's an unexpected behaviour nonetheless).