Select a region in the alignment and choose

• the Edit ‣ Insert gaps item in the context menu or press the Spacebar. The region is filled with gaps shifting the subalignment from the region to the right. Region selection is also moved to the right.
• the Edit ‣ Replace with gaps in the context menu or press the Shift+Spacebar. The region is filled with gaps shifting the subalignment from the region to the right. Region selection is not moved.