diff --git a/modules/global/src/com/haulmont/cuba/security/global/UserSession.java b/modules/global/src/com/haulmont/cuba/security/global/UserSession.java
index 5bedf3fd7f..535f9e769c 100644
--- a/modules/global/src/com/haulmont/cuba/security/global/UserSession.java
+++ b/modules/global/src/com/haulmont/cuba/security/global/UserSession.java
@@ -210,11 +210,14 @@ public class UserSession implements Serializable
 
     /**
      * Get user session attribute. Attribute is a named serializable object bound to session.
-     * @param name attribute name
+     * @param name attribute name, or <code>userId</code> to obtain current or substituted user ID
      * @return attribute value
      */
-    public <T extends Serializable> T getAttribute(String name) {
-        return (T) attributes.get(name);
+    public <T> T getAttribute(String name) {
+        if ("userId".equals(name))
+            return (T) (substitutedUser == null ? user.getId() : substitutedUser.getId());
+        else
+            return (T) attributes.get(name);
     }
 
     /**
diff --git a/modules/gui/src/com/haulmont/cuba/gui/data/impl/AbstractCollectionDatasource.java b/modules/gui/src/com/haulmont/cuba/gui/data/impl/AbstractCollectionDatasource.java
index 06b6488277..d107a09f76 100644
--- a/modules/gui/src/com/haulmont/cuba/gui/data/impl/AbstractCollectionDatasource.java
+++ b/modules/gui/src/com/haulmont/cuba/gui/data/impl/AbstractCollectionDatasource.java
@@ -192,10 +192,7 @@ public abstract class AbstractCollectionDatasource<T extends Entity<K>, K>
                 case SESSION: {
                     Object value;
                     UserSession us = UserSessionClient.getUserSession();
-                    if ("userId".equals(path))
-                        value = us.getSubstitutedUser() != null ? us.getSubstitutedUser().getId() : us.getUser().getId();
-                    else
-                        value = us.getAttribute(path);
+                    value = us.getAttribute(path);
 
                     if (value instanceof String && info.isCaseInsensitive()) {
                         value = makeCaseInsensitive((String) value);
diff --git a/modules/web/src/com/haulmont/cuba/web/gui/components/filter/CustomConditionEditDlg.java b/modules/web/src/com/haulmont/cuba/web/gui/components/filter/CustomConditionEditDlg.java
index dfdf2033de..01bd52b788 100644
--- a/modules/web/src/com/haulmont/cuba/web/gui/components/filter/CustomConditionEditDlg.java
+++ b/modules/web/src/com/haulmont/cuba/web/gui/components/filter/CustomConditionEditDlg.java
@@ -109,7 +109,7 @@ public class CustomConditionEditDlg extends Window {
 
         whereText = new TextField();
         whereText.setWidth(FIELD_WIDTH);
-        whereText.setRows(2);
+        whereText.setRows(4);
         whereText.setNullRepresentation("");
         String where = replaceParamWithQuestionMark(condition.getWhere());
         whereText.setValue(where);
@@ -238,7 +238,13 @@ public class CustomConditionEditDlg extends Window {
         String res = where.trim();
         if (!StringUtils.isBlank(res)) {
             Matcher matcher = QueryParserRegex.PARAM_PATTERN.matcher(res);
-            res = matcher.replaceAll("?");
+            StringBuffer sb = new StringBuffer();
+            while (matcher.find()) {
+                if (!matcher.group().startsWith(":session$"))
+                    matcher.appendReplacement(sb, "?");
+            }
+            matcher.appendTail(sb);
+            return sb.toString();
         }
         return res;
     }
@@ -329,6 +335,8 @@ public class CustomConditionEditDlg extends Window {
                         select.setValue(ParamType.BOOLEAN);
                     else if (Number.class.equals(param.getJavaClass()))
                         select.setValue(ParamType.NUMBER);
+                    else if (UUID.class.equals(param.getJavaClass()))
+                        select.setValue(ParamType.UUID);
                     else
                         throw new UnsupportedOperationException("Unsupported param class: " + param.getJavaClass());
                     break;