diff --git a/src/server/client.ts b/src/server/client.ts
index 2ec0dd4de62..cc89349b442 100644
--- a/src/server/client.ts
+++ b/src/server/client.ts
@@ -527,9 +527,9 @@ namespace ts.server {
             });
         }
 
-        getDocumentHighlights(fileName: string, position: number): DocumentHighlights[] {
+        getDocumentHighlights(fileName: string, position: number, filesToSearch: string[]): DocumentHighlights[] {
             let { line, offset } = this.positionToOneBasedLineOffset(fileName, position);
-            let args: protocol.FileLocationRequestArgs = { file: fileName, line, offset };
+            let args: protocol.DocumentHighlightsRequestArgs = { file: fileName, line, offset, filesToSearch };
 
             let request = this.processRequest<protocol.DocumentHighlightsRequest>(CommandNames.DocumentHighlights, args);
             let response = this.processResponse<protocol.DocumentHighlightsResponse>(request);
diff --git a/src/server/protocol.d.ts b/src/server/protocol.d.ts
index bdabf89a982..837bce4f99d 100644
--- a/src/server/protocol.d.ts
+++ b/src/server/protocol.d.ts
@@ -156,6 +156,17 @@ declare namespace ts.server.protocol {
         arguments: FileLocationRequestArgs;
     }
 
+    /**
+      * Arguments in document highlight request; include: filesToSearch, file,
+      * line, offset.
+      */
+    export interface DocumentHighlightsRequestArgs extends FileLocationRequestArgs {
+        /**
+         * List of files to search for document highlights.
+         */
+        filesToSearch: string[];
+    }
+
     /**
       * Go to definition request; value of command field is
       * "definition". Return response giving the file locations that
@@ -244,6 +255,7 @@ declare namespace ts.server.protocol {
       * in the file at a given line and column.
       */
     export interface DocumentHighlightsRequest extends FileLocationRequest {
+        arguments: DocumentHighlightsRequestArgs
     }
 
     export interface HighlightSpan extends TextSpan {
@@ -251,7 +263,14 @@ declare namespace ts.server.protocol {
     }
 
     export interface DocumentHighlightsItem {
+        /**
+          * File containing highlight spans.
+          */
         file: string,
+
+        /**
+          * Spans to highlight in file.
+          */
         highlightSpans: HighlightSpan[];
     }
 
@@ -259,7 +278,6 @@ declare namespace ts.server.protocol {
         body?: DocumentHighlightsItem[];
     }
 
-
     /**
       * Find references request; value of command field is
       * "references". Return response giving the file locations that
diff --git a/src/server/session.ts b/src/server/session.ts
index 963c443f09b..54e4423d382 100644
--- a/src/server/session.ts
+++ b/src/server/session.ts
@@ -344,7 +344,7 @@ namespace ts.server {
             });
         }
 
-        private getDocumentHighlights(line: number, offset: number, fileName: string): protocol.DocumentHighlightsItem[] {
+        private getDocumentHighlights(line: number, offset: number, fileName: string, filesToSearch: string[]): protocol.DocumentHighlightsItem[] {
             fileName = ts.normalizePath(fileName);
             let project = this.projectService.getProjectForFile(fileName);
 
@@ -354,7 +354,6 @@ namespace ts.server {
 
             let { compilerService } = project;
             let position = compilerService.host.lineOffsetToPosition(fileName, line, offset);
-            let filesToSearch = [ fileName ]; // only search for highlights inside the current file
             
             let documentHighlights = compilerService.languageService.getDocumentHighlights(fileName, position, filesToSearch);
             
@@ -976,8 +975,8 @@ namespace ts.server {
                 return {response: this.getOccurrences(line, offset, fileName), responseRequired: true};
             },
             [CommandNames.DocumentHighlights]: (request: protocol.Request) => {
-                var { line, offset, file: fileName } = <protocol.FileLocationRequestArgs>request.arguments;
-                return {response: this.getDocumentHighlights(line, offset, fileName), responseRequired: true};
+                var { line, offset, file: fileName, filesToSearch } = <protocol.DocumentHighlightsRequestArgs>request.arguments;
+                return {response: this.getDocumentHighlights(line, offset, fileName, filesToSearch), responseRequired: true};
             },
             [CommandNames.ProjectInfo]: (request: protocol.Request) => {
                 var { file, needFileNameList } = <protocol.ProjectInfoRequestArgs>request.arguments;
diff --git a/tests/cases/fourslash/server/documentHighlights02.ts b/tests/cases/fourslash/server/documentHighlights02.ts
index 8cf7038395a..357f82e9c2d 100644
--- a/tests/cases/fourslash/server/documentHighlights02.ts
+++ b/tests/cases/fourslash/server/documentHighlights02.ts
@@ -1,23 +1,35 @@
 /// <reference path="../fourslash.ts"/>
 
 // @Filename: a.ts
-////function foo() {
+////function [|foo|] () {
 ////	return 1;
 ////}
+////[|foo|]();
 
 // @Filename: b.ts
 /////// <reference path="a.ts"/>
-////[|foo|]();
+////foo();
 
+// open two files
+goTo.file("a.ts");
+goTo.file("b.ts");
 
 let ranges = test.ranges();
 
-for (let r of ranges) {
+for (let i = 0; i < ranges.length; ++i) {
+	let r = ranges[i];
+
+	if (i < 2) {
+		goTo.file("a.ts");
+	}
+	else {
+		goTo.file("b.ts");
+	}
+
     goTo.position(r.start);
-    verify.documentHighlightsAtPositionCount(2, ["b.ts"]);
+    verify.documentHighlightsAtPositionCount(3, ["a.ts", "b.ts"]);
 
-    /*for (let range of ranges) {
-        verify.documentHighlightsAtPositionContains(range, ["a.ts"]);
-    }*/
+    for (let range of ranges) {
+        verify.documentHighlightsAtPositionContains(range, ["a.ts", "b.ts"]);
+    }
 }
-