diff --git a/grid.c b/grid.c
index c26db476..aa9aea4c 100644
--- a/grid.c
+++ b/grid.c
@@ -292,12 +292,14 @@ grid_collect_history(struct grid *gd)
 {
 	u_int	ny;
 
-	if (gd->hsize < gd->hlimit)
+	if (gd->hsize == 0 || gd->hsize < gd->hlimit)
 		return;
 
 	ny = gd->hlimit / 10;
 	if (ny < 1)
 		ny = 1;
+	if (ny > gd->hsize)
+		ny = gd->hsize;
 
 	/*
 	 * Free the lines from 0 to ny then move the remaining lines over
diff --git a/tmux.1 b/tmux.1
index 08c67a6f..49a5350a 100644
--- a/tmux.1
+++ b/tmux.1
@@ -1407,7 +1407,9 @@ specifies the initial sort order: one of
 or
 .Ql activity .
 .Fl f
-specifies an initial filter.
+specifies an initial filter: the filter is a format - if it evaluates to zero,
+the item in the list is not shown, otherwise it is shown.
+If a filter would lead to an empty list, it is ignored.
 .Fl F
 specifies the format for each item in the list.
 .Fl N
@@ -1464,7 +1466,9 @@ specifies the initial sort order: one of
 or
 .Ql time .
 .Fl f
-specifies an initial filter.
+specifies an initial filter: the filter is a format - if it evaluates to zero,
+the item in the list is not shown, otherwise it is shown.
+If a filter would lead to an empty list, it is ignored.
 .Fl F
 specifies the format for each item in the tree.
 .Fl N
@@ -4117,7 +4121,9 @@ specifies the initial sort order: one of
 or
 .Ql size .
 .Fl f
-specifies an initial filter.
+specifies an initial filter: the filter is a format - if it evaluates to zero,
+the item in the list is not shown, otherwise it is shown.
+If a filter would lead to an empty list, it is ignored.
 .Fl F
 specifies the format for each item in the list.
 .Fl N