Avoid removing whole document when user scrolls using the scrollbar

Former-commit-id: 553124a0385b4c74e57042e4c03d19a720babfd6

extension/ui/content/content-ui-editor-web.js

@@ -430,8 +430,10 @@
 		}
 		if (cuttingMode) {
 			let element = event.target;
-			element.classList.add ("single-file-removed");
-			removedElements.push(element);
+			if (document.documentElement != element) {
+				element.classList.add ("single-file-removed");
+				removedElements.push(element);
+			}
 		}
 	}