No, and that is deliberate. In SimpleGantt the table is the single source of truth for the plan. Dragging bars would create a second place where dates change, and the two would drift apart, especially when dates come from formulas or other sheets.
Editing is still quick:
- Click the bar. SimpleGantt selects that task’s row in the sheet.
- Double-click the bar to go straight to its start date.
- Type the new date. The chart redraws at once.
Dates that follow from predecessors do not have to be typed at all: leave the start empty and SimpleGantt calculates it (a Pro feature).