diff --git a/cmd-clear-history.c b/cmd-clear-history.c
index 88dbbcf7..63e9d548 100644
--- a/cmd-clear-history.c
+++ b/cmd-clear-history.c
@@ -47,9 +47,7 @@ cmd_clear_history_exec(struct cmd *self, struct cmd_q *cmdq)
 
 	if (wp->mode == &window_copy_mode)
 		window_pane_reset_mode(wp);
-
-	grid_move_lines(gd, 0, gd->hsize, gd->sy);
-	gd->hsize = 0;
+	grid_clear_history(gd);
 
 	return (CMD_RETURN_NORMAL);
 }
diff --git a/grid.c b/grid.c
index 93fed05e..99dafab2 100644
--- a/grid.c
+++ b/grid.c
@@ -170,6 +170,18 @@ grid_scroll_history(struct grid *gd)
 	gd->hsize++;
 }
 
+/* Clear the history. */
+void
+grid_clear_history(struct grid *gd)
+{
+	grid_clear_lines(gd, 0, gd->hsize);
+	grid_move_lines(gd, 0, gd->hsize, gd->sy);
+
+	gd->hsize = 0;
+	gd->linedata = xreallocarray(gd->linedata, gd->sy,
+	    sizeof *gd->linedata);
+}
+
 /* Scroll a region up, moving the top line into the history. */
 void
 grid_scroll_history_region(struct grid *gd, u_int upper, u_int lower)
@@ -344,8 +356,8 @@ grid_move_lines(struct grid *gd, u_int dy, u_int py, u_int ny)
 		grid_clear_lines(gd, yy, 1);
 	}
 
-	memmove(
-	    &gd->linedata[dy], &gd->linedata[py], ny * (sizeof *gd->linedata));
+	memmove(&gd->linedata[dy], &gd->linedata[py],
+	    ny * (sizeof *gd->linedata));
 
 	/* Wipe any lines that have been moved (without freeing them). */
 	for (yy = py; yy < py + ny; yy++) {
@@ -371,8 +383,8 @@ grid_move_cells(struct grid *gd, u_int dx, u_int px, u_int py, u_int nx)
 
 	grid_expand_line(gd, py, px + nx);
 	grid_expand_line(gd, py, dx + nx);
-	memmove(
-	    &gl->celldata[dx], &gl->celldata[px], nx * sizeof *gl->celldata);
+	memmove(&gl->celldata[dx], &gl->celldata[px],
+	    nx * sizeof *gl->celldata);
 
 	/* Wipe any cells that have been moved. */
 	for (xx = px; xx < px + nx; xx++) {
diff --git a/tmux.h b/tmux.h
index 3fd057e9..5bf9b39b 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1842,6 +1842,7 @@ int	 grid_compare(struct grid *, struct grid *);
 void	 grid_collect_history(struct grid *);
 void	 grid_scroll_history(struct grid *);
 void	 grid_scroll_history_region(struct grid *, u_int, u_int);
+void	 grid_clear_history(struct grid *);
 void	 grid_expand_line(struct grid *, u_int, u_int);
 const struct grid_cell *grid_peek_cell(struct grid *, u_int, u_int);
 const struct grid_line *grid_peek_line(struct grid *, u_int);