use a class

addons/xterm-addon-search/src/SearchAddon.ts

@@ -539,10 +539,12 @@ export class SearchAddon implements ITerminalAddon {
     }
     const findResultDecoration = terminal.registerDecoration({ marker });
     findResultDecoration?.onRender((e) => {
-      e.style.backgroundColor = 'blue';
-      e.style.opacity = '60%';
-      e.style.left = `${result.col * e.clientWidth}px`;
-      e.style.width = `${e.clientWidth * result.term.length}px`;
+      if (!e.classList.contains('xterm-find-result-decoration')) {
+        e.classList.add('xterm-find-result-decoration');
+        // decoration's clientWidth = actualCellWidth
+        e.style.left = `${e.clientWidth * result.col}px`;
+        e.style.width = `${e.clientWidth * result.term.length}px`;
+      }
     });
     return findResultDecoration;
   }

css/xterm.css

@@ -178,3 +178,8 @@
 	z-index: 6;
 	position: absolute;
 }
+
+.xterm-find-result-decoration {
+   background-color: blue;
+   opacity: 60%;
+}