diff --git a/extensions/vscode-api-tests/src/singlefolder-tests/workspace.test.ts b/extensions/vscode-api-tests/src/singlefolder-tests/workspace.test.ts
index fbfe2e98bab2fb1bff151290cea422cd17975e24..cfa5c3356c52e8acf33b9fc869364403547bb094 100644
--- a/extensions/vscode-api-tests/src/singlefolder-tests/workspace.test.ts
+++ b/extensions/vscode-api-tests/src/singlefolder-tests/workspace.test.ts
@@ -514,7 +514,6 @@ suite('workspace-namespace', () => {
 		const options: vscode.FindTextInFilesOptions = {
 			include: '*.ts',
 			previewOptions: {
-				leadingChars: 2,
 				maxLines: 1,
 				totalChars: 100
 			}
@@ -526,7 +525,7 @@ suite('workspace-namespace', () => {
 		});
 
 		assert.equal(results.length, 1);
-		assert.equal(results[0].preview.text, 'n foo(): void {');
+		assert(results[0].preview.text.indexOf('foo') >= 0);
 		assert.equal(vscode.workspace.asRelativePath(results[0].uri), '10linefile.ts');
 	});
 
diff --git a/src/vs/workbench/api/node/extHostWorkspace.ts b/src/vs/workbench/api/node/extHostWorkspace.ts
index 319cd7145299b1746b8f9e71955e0d3ef70090a0..489395425732782f1b6472927566772d58987e65 100644
--- a/src/vs/workbench/api/node/extHostWorkspace.ts
+++ b/src/vs/workbench/api/node/extHostWorkspace.ts
@@ -394,13 +394,20 @@ export class ExtHostWorkspace implements ExtHostWorkspaceShape {
 			return join(pattern.base, pattern.pattern);
 		};
 
+		const previewOptions: vscode.TextSearchPreviewOptions = typeof options.previewOptions === 'undefined' ?
+			{
+				maxLines: 100,
+				totalChars: 10000
+			} :
+			options.previewOptions;
+
 		const queryOptions: IQueryOptions = {
 			ignoreSymlinks: typeof options.followSymlinks === 'boolean' ? !options.followSymlinks : undefined,
 			disregardIgnoreFiles: typeof options.useIgnoreFiles === 'boolean' ? !options.useIgnoreFiles : undefined,
 			disregardExcludeSettings: options.exclude === null,
 			fileEncoding: options.encoding,
 			maxResults: options.maxResults,
-			previewOptions: options.previewOptions,
+			previewOptions,
 
 			includePattern: options.include && globPatternToString(options.include),
 			excludePattern: options.exclude && globPatternToString(options.exclude)