diff --git a/pkg/gui/view_helpers.go b/pkg/gui/view_helpers.go
index 9d70b6e4b..ed4002748 100644
--- a/pkg/gui/view_helpers.go
+++ b/pkg/gui/view_helpers.go
@@ -44,10 +44,12 @@ func (gui *Gui) linesToReadFromCmdTask(v *gocui.View) tasks.LinesToRead {
 	linesToReadForAccurateScrollbar := min(
 		// However, cap it at some arbitrary max limit, so that we don't get
 		// performance problems for huge monitors or tiny font sizes
-		height*(height-1)/minScrollbarHeight+oy, 5000)
+		height*(height-1)/minScrollbarHeight, 5000) + oy
 
 	return tasks.LinesToRead{
-		Total:               linesToReadForAccurateScrollbar,
+		// A view no more than a few lines tall needs fewer lines for its scrollbar
+		// than it takes to fill it, and the task must read at least those.
+		Total:               max(linesToReadForAccurateScrollbar, linesForFirstRefresh),
 		InitialRefreshAfter: linesForFirstRefresh,
 	}
 }
diff --git a/pkg/integration/tests/main_view/show_another_long_diff_after_scrolling_far_down.go b/pkg/integration/tests/main_view/show_another_long_diff_after_scrolling_far_down.go
index 094cb99ba..2f0580663 100644
--- a/pkg/integration/tests/main_view/show_another_long_diff_after_scrolling_far_down.go
+++ b/pkg/integration/tests/main_view/show_another_long_diff_after_scrolling_far_down.go
@@ -47,9 +47,6 @@ var ShowAnotherLongDiffAfterScrollingFarDown = NewIntegrationTest(NewIntegration
 			SelectedLine(Contains("first commit"))
 
 		t.Views().Main().
-			/* EXPECTED:
 			Content(Contains("diff --git a/first.txt b/first.txt"))
-			ACTUAL: */
-			Content(Contains("diff --git a/second.txt b/second.txt"))
 	},
 })
diff --git a/pkg/tasks/tasks.go b/pkg/tasks/tasks.go
index 510fffa49..7e0c10676 100644
--- a/pkg/tasks/tasks.go
+++ b/pkg/tasks/tasks.go
@@ -167,6 +167,11 @@ type LinesToRead struct {
 	// Number of lines after which we have read enough to fill the view, and can
 	// do an initial refresh. Only set for the initial read request; -1 for
 	// subsequent requests.
+	//
+	// Unless Total is -1, it must not be more than Total. The task shows nothing
+	// of what it reads until it has read this many lines or has reached the end
+	// of its input, so a task that stops reading before then leaves the view
+	// showing the previous render.
 	InitialRefreshAfter int
 
 	// Function to call after reading the lines is done