diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/MaterialChooserField.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/MaterialChooserField.java
index 016e7738e80f7bc68ee477095840350c51807c52..b0fb4f396f52fd41a2d99989a2d7a2820c8901cc 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/MaterialChooserField.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/field/MaterialChooserField.java
@@ -69,8 +69,8 @@ public class MaterialChooserField extends ChosenEntitySetter<Material>
     // ------------------
 
     // the pattern used to validate material identifier expression
-    private final static String CODE_AND_TYPE_PATTERN = CodeField.CODE_CHARS + " " + "\\("
-            + CodeField.CODE_CHARS + "\\)";
+    private final static String CODE_AND_TYPE_PATTERN = "^[^\\s]+ \\(" + CodeField.CODE_CHARS
+            + "\\)$";
 
     @Override
     public String renderEntity(Material materialOrNull)