remove highlights if content changes

apps/remix-ide/src/app/editor/SourceHighlighters.js

@@ -50,6 +50,12 @@ class SourceHighlighters {
     this.highlighters[from] = []
   }
 
+  discardAllHighlights () {
+    for (const from in this.highlighters) {
+      this.discardHighlight(from)
+    }
+  }
+
   hideHighlightsExcept (toStay) {
     for (const highlighter in this.highlighters) {
       for (const index in this.highlighters[highlighter]) {

apps/remix-ide/src/app/editor/editor.js

@@ -191,6 +191,7 @@ class Editor extends Plugin {
       this.event.trigger('sessionSwitched', [])
       this.editor.getSession().on('change', () => {
         this._onChange()
+        this.sourceHighlighters.discardAllHighlights()
         this.event.trigger('contentChanged', [])
       })
     })