Storyboarding and the Story Reel - Animating with Blender: How to Create Short Animations from Start to Finish - page 51

Figure 4.49 Adjusting the handles to lengthen and shorten sequence strips
Sequence strips may also be selected and moved in groups. The standard right mouse button and B key selec-
tion methods apply. Selected strips can be deleted with the X key or duplicated with Shift-D .
When moving a sequence strip (or several at once), Blender will not allow you to move it into a space already
occupied by another strip. If this happens, the outline of the moving strip will turn red as a warning. If you
accept the transform by pressing the left mouse button while the strips are overlapping, the moved strip will
be automatically placed adjacent to the blocking strip, if there is room, or put into a neighboring channel if
there is not (Figures 4.50-4.51).
Figure 4.50 A strip transforming to overlap will be outlined in red