diff --git a/ui/graphview.cpp b/ui/graphview.cpp
index 7b1783714..c91a1d0c0 100644
--- a/ui/graphview.cpp
+++ b/ui/graphview.cpp
@@ -524,9 +524,9 @@ void GraphView::mouseMoveEvent(QMouseEvent *event) {
 				}
 
 				EffectKeyframe& key = row->field(handle_field)->keyframes[handle_index];
-				key.pre_handle_x = new_pre_handle_x;
+				key.pre_handle_x = qMin(0.0, new_pre_handle_x);
 				key.pre_handle_y = new_pre_handle_y;
-				key.post_handle_x = new_post_handle_x;
+				key.post_handle_x = qMax(0.0, new_post_handle_x);
 				key.post_handle_y = new_post_handle_y;
 
 				moved_keys = true;