diff --git a/src/Tools/tim_tool/ui/tab/main-tab.slint b/src/Tools/tim_tool/ui/tab/main-tab.slint
index e28282cc..fdd28332 100644
--- a/src/Tools/tim_tool/ui/tab/main-tab.slint
+++ b/src/Tools/tim_tool/ui/tab/main-tab.slint
@@ -112,11 +112,11 @@ export component MainTab inherits Rectangle {
 
                 function update_viewport() {
                     if abs(self.viewport-x) + self.width > self.viewport-width {
-                        self.viewport-x = 0;
+                        self.viewport-x += (self.width + abs(self.viewport-x)) - self.viewport-width;
                     }
 
                     if abs(self.viewport-y) + self.height > self.viewport-height {
-                        self.viewport-y = 0;
+                        self.viewport-y += (self.height + abs(self.viewport-y)) - self.viewport-height;
                     }
                 }
             }