diff --git a/src/AddIns/BackendBindings/WixBinding/Project/Src/WixBinaries.cs b/src/AddIns/BackendBindings/WixBinding/Project/Src/WixBinaries.cs
index 709e197270..485d78dbb3 100644
--- a/src/AddIns/BackendBindings/WixBinding/Project/Src/WixBinaries.cs
+++ b/src/AddIns/BackendBindings/WixBinding/Project/Src/WixBinaries.cs
@@ -82,9 +82,11 @@ namespace ICSharpCode.WixBinding
 		List<string> GetWixFileNamesInProject(WixDocument document)
 		{
 			List<string> fileNames = new List<string>();
-			foreach (FileProjectItem fileProjectItem in project.WixFiles) {
-				if (!FileUtility.IsEqualFileName(fileProjectItem.FileName, document.FileName)) {
-					fileNames.Add(fileProjectItem.FileName);
+			if (project != null) {
+				foreach (FileProjectItem fileProjectItem in project.WixFiles) {
+					if (!FileUtility.IsEqualFileName(fileProjectItem.FileName, document.FileName)) {
+						fileNames.Add(fileProjectItem.FileName);
+					}
 				}
 			}
 			return fileNames;
diff --git a/src/AddIns/BackendBindings/WixBinding/Test/Document/GetBinaryFileNameFromProjectTestFixture.cs b/src/AddIns/BackendBindings/WixBinding/Test/Document/GetBinaryFileNameFromProjectTestFixture.cs
index 19933b331b..a1f92872b9 100644
--- a/src/AddIns/BackendBindings/WixBinding/Test/Document/GetBinaryFileNameFromProjectTestFixture.cs
+++ b/src/AddIns/BackendBindings/WixBinding/Test/Document/GetBinaryFileNameFromProjectTestFixture.cs
@@ -71,6 +71,19 @@ namespace WixBinding.Tests.Document
 			Assert.AreEqual(expectedFileName, binaries.GetBinaryFileName("Dialog"));
 		}
 		
+		/// <summary>
+		/// SD2-1267 - If you open a single WiX file (.wxs) without opening 
+		/// a WiX project you are unable to design its WiX dialog. 
+		/// </summary>
+		[Test]
+		public void GetBinaryFileNameWhenWixDocNotInProject()
+		{
+			WixDocument doc = new WixDocument();
+			WixBinaries binaries = new WixBinaries(doc, this);
+			
+			Assert.IsNull(binaries.GetBinaryFileName("UnknownId"));
+		}
+		
 		public TextReader Create(string fileName)
 		{
 			fileName = Path.GetFileName(fileName);