diff --git a/skyquake/plugins/composer/src/src/components/EditDescriptorModelProperties.js b/skyquake/plugins/composer/src/src/components/EditDescriptorModelProperties.js
index 4ee4345..d04dddf 100644
--- a/skyquake/plugins/composer/src/src/components/EditDescriptorModelProperties.js
+++ b/skyquake/plugins/composer/src/src/components/EditDescriptorModelProperties.js
@@ -178,8 +178,8 @@
 		let catalogs = cds.getTransientCatalogs();
 
 		const name = path.join('.');
-		const isEditable = true;
 		const isGuid = Property.isGuid(property);
+		const isEditable = isGuid;
 		const onChange = onFormFieldValueChanged.bind(container);
 		const isEnumeration = Property.isEnumeration(property);
 		const isLeafRef = Property.isLeafRef(property);
diff --git a/skyquake/plugins/composer/src/src/styles/EditDescriptorModelProperties.scss b/skyquake/plugins/composer/src/src/styles/EditDescriptorModelProperties.scss
index 48ce949..fcca9ef 100644
--- a/skyquake/plugins/composer/src/src/styles/EditDescriptorModelProperties.scss
+++ b/skyquake/plugins/composer/src/src/styles/EditDescriptorModelProperties.scss
@@ -305,5 +305,8 @@
 		font-size: 10px;
 		font-family: monospace;
 	}
+	input[readonly='readonly'] {
+		background-color: $readonly-background-color;
+	}
 
 }
diff --git a/skyquake/plugins/composer/src/src/styles/_ColorGroups.scss b/skyquake/plugins/composer/src/src/styles/_ColorGroups.scss
index b0ea3fb..fe3ded4 100644
--- a/skyquake/plugins/composer/src/src/styles/_ColorGroups.scss
+++ b/skyquake/plugins/composer/src/src/styles/_ColorGroups.scss
@@ -28,4 +28,6 @@
 $common-primary-color: black;
 $common-secondary-color: white;
 $common-background-color: white;
-$common-foreground-color: black;
\ No newline at end of file
+$common-foreground-color: black;
+
+$readonly-background-color: #ffe;
\ No newline at end of file