diff --git a/src/editor/manager.test.ts b/src/editor/manager.test.ts
new file mode 100644
index 0000000000..d214ba5ec6
--- /dev/null
+++ b/src/editor/manager.test.ts
@@ -0,0 +1,81 @@
+import { editorManager } from 'lib/singletons'
+import { Diagnostic } from '@codemirror/lint'
+
+describe('EditorManager Class', () => {
+  describe('makeUniqueDiagnostics', () => {
+    it('should filter out duplicated diagnostics', () => {
+      const duplicatedDiagnostics: Diagnostic[] = [
+        {
+          from: 2,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+        {
+          from: 2,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+        {
+          from: 2,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+      ]
+
+      const expected: Diagnostic[] = [
+        {
+          from: 2,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+      ]
+
+      const actual = editorManager.makeUniqueDiagnostics(duplicatedDiagnostics)
+      expect(actual).toStrictEqual(expected)
+    })
+    it('should filter out duplicated diagnostic and keep some original ones', () => {
+      const duplicatedDiagnostics: Diagnostic[] = [
+        {
+          from: 0,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+        {
+          from: 0,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+        {
+          from: 88,
+          to: 99,
+          severity: 'hint',
+          message: 'my super cool message',
+        },
+      ]
+
+      const expected: Diagnostic[] = [
+        {
+          from: 0,
+          to: 10,
+          severity: 'hint',
+          message: 'my cool message',
+        },
+        {
+          from: 88,
+          to: 99,
+          severity: 'hint',
+          message: 'my super cool message',
+        },
+      ]
+
+      const actual = editorManager.makeUniqueDiagnostics(duplicatedDiagnostics)
+      expect(actual).toStrictEqual(expected)
+    })
+  })
+})
diff --git a/src/editor/manager.ts b/src/editor/manager.ts
index 4ed81375c8..8b2c1c9811 100644
--- a/src/editor/manager.ts
+++ b/src/editor/manager.ts
@@ -22,10 +22,6 @@ export const modelingMachineEvent = modelingMachineAnnotation.of(true)
 const setDiagnosticsAnnotation = Annotation.define<boolean>()
 export const setDiagnosticsEvent = setDiagnosticsAnnotation.of(true)
 
-function diagnosticIsEqual(d1: Diagnostic, d2: Diagnostic): boolean {
-  return d1.from === d2.from && d1.to === d2.to && d1.message === d2.message
-}
-
 export default class EditorManager {
   private _editorView: EditorView | null = null
   private _copilotEnabled: boolean = true
@@ -117,20 +113,29 @@ export default class EditorManager {
     }
   }
 
+  /**
+   * Given an array of Diagnostics remove any duplicates by hashing a key
+   * in the format of from + ' ' + to + ' ' + message.
+   */
+  makeUniqueDiagnostics(duplicatedDiagnostics: Diagnostic[]): Diagnostic[] {
+    const uniqueDiagnostics: Diagnostic[] = []
+    const seenDiagnostic: { [key: string]: boolean } = {}
+
+    duplicatedDiagnostics.forEach((diagnostic: Diagnostic) => {
+      const hash = `${diagnostic.from} ${diagnostic.to} ${diagnostic.message}`
+      if (!seenDiagnostic[hash]) {
+        uniqueDiagnostics.push(diagnostic)
+        seenDiagnostic[hash] = true
+      }
+    })
+
+    return uniqueDiagnostics
+  }
+
   setDiagnostics(diagnostics: Diagnostic[]): void {
     if (!this._editorView) return
     // Clear out any existing diagnostics that are the same.
-    for (const diagnostic of diagnostics) {
-      for (const otherDiagnostic of diagnostics) {
-        if (diagnosticIsEqual(diagnostic, otherDiagnostic)) {
-          diagnostics = diagnostics.filter(
-            (d) => !diagnosticIsEqual(d, diagnostic)
-          )
-          diagnostics.push(diagnostic)
-          break
-        }
-      }
-    }
+    diagnostics = this.makeUniqueDiagnostics(diagnostics)
 
     this._editorView.dispatch({
       effects: [setDiagnosticsEffect.of(diagnostics)],
diff --git a/src/lang/KclSingleton.ts b/src/lang/KclSingleton.ts
index 1d55ad2537..b1b9feaae9 100644
--- a/src/lang/KclSingleton.ts
+++ b/src/lang/KclSingleton.ts
@@ -124,7 +124,7 @@ export class KclManager {
     if (this.lints.length > 0) {
       diagnostics = diagnostics.concat(this.lints)
     }
-    editorManager.setDiagnostics(diagnostics)
+    editorManager?.setDiagnostics(diagnostics)
   }
 
   addKclErrors(kclErrors: KCLError[]) {