diff --git a/packages/server/src/VDF/VDFLanguageServer.ts b/packages/server/src/VDF/VDFLanguageServer.ts
index a1f939a..2a87dc6 100644
--- a/packages/server/src/VDF/VDFLanguageServer.ts
+++ b/packages/server/src/VDF/VDFLanguageServer.ts
@@ -111,7 +111,7 @@ export abstract class VDFLanguageServer<
 					// @ts-ignore
 					return [
 						...(value.reference ? value.reference.flatMap(include) : []),
-						...value.values.filter((value) => (text ? value.label.toLowerCase().startsWith(text.toLowerCase()) : true) && (value.multiple ? true : !documentSymbol.children?.some((d) => d.key.toLowerCase() == value.label.toLowerCase())))
+						...value.values?.filter((value) => (text ? value.label.toLowerCase().startsWith(text.toLowerCase()) : true) && (value.multiple ? true : !documentSymbol.children?.some((d) => d.key.toLowerCase() == value.label.toLowerCase()))) ?? []
 					]
 				}
 
diff --git a/packages/server/src/VDF/VDFTextDocument.ts b/packages/server/src/VDF/VDFTextDocument.ts
index c7bcdf0..db2044e 100644
--- a/packages/server/src/VDF/VDFTextDocument.ts
+++ b/packages/server/src/VDF/VDFTextDocument.ts
@@ -48,7 +48,7 @@ export interface VDFTextDocumentDependencies {
 }
 
 export interface VDFTextDocumentSchema {
-	keys: Record<string, { reference?: string[], values: { label: string, kind: number, multiple?: boolean }[] }>
+	keys: Record<string, { distinct?: boolean, reference?: string[], values?: { label: string, kind: number, multiple?: boolean }[] }>
 	values: Record<string, { kind: number, enumIndex?: boolean, values: string[], fix?: Record<string, string> }>
 	definitionReferences: {
 		type: symbol
@@ -386,6 +386,41 @@ export abstract class VDFTextDocument<TDocument extends VDFTextDocument<TDocumen
 						const documentSymbolKey = configuration.keyTransform(documentSymbol.key.toLowerCase())
 						const documentSymbolValue = documentSymbol.detail.toLowerCase()
 
+						// Distinct Keys
+						if (documentSymbolKey in dependencies.schema.keys && dependencies.schema.keys[documentSymbolKey].distinct == true) {
+							const parent = path.at(-1)
+							if (parent?.children != undefined) {
+								const first = parent.children.find((i) => configuration.keyTransform(i.key.toLowerCase()) == documentSymbolKey && i.conditional?.toLowerCase() == documentSymbol.conditional?.toLowerCase())!
+								if (first != documentSymbol) {
+									diagnostics.push({
+										range: documentSymbol.nameRange,
+										severity: DiagnosticSeverity.Warning,
+										code: "duplicate-key",
+										source: init.languageId,
+										message: `Duplicate ${first.key}`,
+										relatedInformation: [
+											{
+												location: {
+													uri: this.uri.toString(),
+													range: first.nameRange
+												},
+												message: `${first.key} is declared here.`
+											}
+										],
+										data: {
+											kind: CodeActionKind.QuickFix,
+											fix: (createDocumentWorkspaceEdit) => {
+												return {
+													title: `Remove duplicate ${documentSymbol.key}`,
+													edit: createDocumentWorkspaceEdit(documentSymbol.range, "")
+												}
+											}
+										}
+									})
+								}
+							}
+						}
+
 						// Static
 						if (documentSymbolKey in dependencies.schema.values) {
 							const valueData = dependencies.schema.values[documentSymbolKey]
diff --git a/packages/server/src/VDF/VGUI/keys.json b/packages/server/src/VDF/VGUI/keys.json
index 4aa1d6b..6e9a172 100644
--- a/packages/server/src/VDF/VGUI/keys.json
+++ b/packages/server/src/VDF/VGUI/keys.json
@@ -1,4 +1,7 @@
 {
+    "autoresize": {
+        "distinct": true
+    },
     "button": {
         "reference": [
             "cexlabel"
@@ -48,6 +51,9 @@
             }
         ]
     },
+    "controlname": {
+        "distinct": true
+    },
     "ctfimagepanel": {
         "reference": [
             "imagepanel"
@@ -82,6 +88,12 @@
             }
         ]
     },
+    "enabled": {
+        "distinct": true
+    },
+    "fieldname": {
+        "distinct": true
+    },
     "imagepanel": {
         "reference": [
             "panel"
@@ -263,5 +275,26 @@
                 "kind": 5
             }
         ]
+    },
+    "pincorner": {
+        "distinct": true
+    },
+    "tall": {
+        "distinct": true
+    },
+    "visible": {
+        "distinct": true
+    },
+    "wide": {
+        "distinct": true
+    },
+    "xpos": {
+        "distinct": true
+    },
+    "ypos": {
+        "distinct": true
+    },
+    "zpos": {
+        "distinct": true
     }
 }