diff --git a/src/vs/vscode.d.ts b/src/vs/vscode.d.ts
index e45661243b5e..4f75113b73ab 100644
--- a/src/vs/vscode.d.ts
+++ b/src/vs/vscode.d.ts
@@ -855,7 +855,7 @@ declare namespace vscode {
 	export interface DecorationOptions {
 
 		/**
-		 * Range to which this decoration is applied.
+		 * Range to which this decoration is applied. The range must not be empty.
 		 */
 		range: Range;