diff --git a/rapidoid-gui/src/main/java/org/rapidoid/gui/Field.java b/rapidoid-gui/src/main/java/org/rapidoid/gui/Field.java
index 02ea057249..936740c8ed 100644
--- a/rapidoid-gui/src/main/java/org/rapidoid/gui/Field.java
+++ b/rapidoid-gui/src/main/java/org/rapidoid/gui/Field.java
@@ -103,8 +103,7 @@ private Var<?> initVar(Item item, Property prop) {
 			return Models.propertyVar(varName, item, prop.name(), initValue);
 
 		} catch (Exception e) {
-			// FIXME x.errors().put(varName, "Invalid value!");
-			Log.warn("Invalid value for property: " + prop.name(), e);
+			prop.errors().add("Invalid value!");
 			return Models.propertyVar(varName, item, prop.name(), null);
 		}
 	}
@@ -164,7 +163,7 @@ protected Tag field(String name, String desc, FieldType type, Collection<?> opti
 			inputWrap = layout == FormLayout.HORIZONTAL ? div(inp).class_("col-sm-8") : inp;
 		}
 
-		Tag err = span("").class_("field-error");
+		Tag err = span(U.join(", ", prop.errors())).class_("field-error");
 		Tag group = lbl != null ? div(lbl, inputWrap, err) : div(inputWrap, err);
 		group = group.class_("form-group");
 		return group;
diff --git a/rapidoid-gui/src/main/java/org/rapidoid/model/Property.java b/rapidoid-gui/src/main/java/org/rapidoid/model/Property.java
index cfcef7ff86..f18a90c074 100644
--- a/rapidoid-gui/src/main/java/org/rapidoid/model/Property.java
+++ b/rapidoid-gui/src/main/java/org/rapidoid/model/Property.java
@@ -6,6 +6,7 @@
 import java.io.Serializable;
 import java.lang.annotation.Annotation;
 import java.lang.reflect.ParameterizedType;
+import java.util.Set;
 
 /*
  * #%L
@@ -43,4 +44,6 @@ public interface Property extends Serializable {
 
 	Object get(Item item);
 
+	Set<String> errors();
+
 }
diff --git a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/AbstractProperty.java b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/AbstractProperty.java
new file mode 100644
index 0000000000..9c278dab3e
--- /dev/null
+++ b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/AbstractProperty.java
@@ -0,0 +1,17 @@
+package org.rapidoid.model.impl;
+
+import org.rapidoid.model.Property;
+import org.rapidoid.u.U;
+
+import java.util.Set;
+
+public abstract class AbstractProperty implements Property {
+
+	private final Set<String> errors = U.set();
+
+	@Override
+	public Set<String> errors() {
+		return errors;
+	}
+
+}
diff --git a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BeanProperty.java b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BeanProperty.java
index cfab9207a7..986388373e 100644
--- a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BeanProperty.java
+++ b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BeanProperty.java
@@ -24,14 +24,13 @@
 import org.rapidoid.annotation.Since;
 import org.rapidoid.commons.Str;
 import org.rapidoid.model.Item;
-import org.rapidoid.model.Property;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.ParameterizedType;
 
 @Authors("Nikolche Mihajlovski")
 @Since("2.0.0")
-public class BeanProperty implements Property {
+public class BeanProperty extends AbstractProperty {
 
 	private static final long serialVersionUID = 7627370931428864929L;
 
diff --git a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BuiltInProperty.java b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BuiltInProperty.java
index 866b1d95c8..bd5e662d8f 100644
--- a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BuiltInProperty.java
+++ b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/BuiltInProperty.java
@@ -23,14 +23,13 @@
 import org.rapidoid.annotation.Authors;
 import org.rapidoid.annotation.Since;
 import org.rapidoid.model.Item;
-import org.rapidoid.model.Property;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.ParameterizedType;
 
 @Authors("Nikolche Mihajlovski")
 @Since("2.2.0")
-public class BuiltInProperty implements Property {
+public class BuiltInProperty extends AbstractProperty {
 
 	private static final long serialVersionUID = -2697490242616488024L;
 
diff --git a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/CalcProperty.java b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/CalcProperty.java
index ce4327bb74..8c150e666f 100644
--- a/rapidoid-gui/src/main/java/org/rapidoid/model/impl/CalcProperty.java
+++ b/rapidoid-gui/src/main/java/org/rapidoid/model/impl/CalcProperty.java
@@ -25,14 +25,13 @@
 import org.rapidoid.lambda.Calc;
 import org.rapidoid.lambda.Lmbd;
 import org.rapidoid.model.Item;
-import org.rapidoid.model.Property;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.ParameterizedType;
 
 @Authors("Nikolche Mihajlovski")
 @Since("2.2.0")
-public class CalcProperty implements Property {
+public class CalcProperty extends AbstractProperty {
 
 	private static final long serialVersionUID = -2697490242616488024L;
 
diff --git a/rapidoid-http-fast/src/main/java/org/rapidoid/http/HttpUtils.java b/rapidoid-http-fast/src/main/java/org/rapidoid/http/HttpUtils.java
index 9624d91139..31646dd30d 100644
--- a/rapidoid-http-fast/src/main/java/org/rapidoid/http/HttpUtils.java
+++ b/rapidoid-http-fast/src/main/java/org/rapidoid/http/HttpUtils.java
@@ -202,11 +202,7 @@ private static void postProcessRedirect(Resp resp) {
 		}
 	}
 
-	public static boolean isDevMode(Req x) {
-		return Conf.dev();
-	}
-
-	public static final void reload(Req x) {
+	public static void reload(Req x) {
 		Map<String, String> sel = U.map("body", PAGE_RELOAD);
 		x.response().json(U.map("_sel_", sel));
 	}
@@ -215,8 +211,8 @@ public static String constructUrl(Req x, String path) {
 		return (Conf.is("https") ? "https://" : "http://") + x.host() + path;
 	}
 
-	public static boolean hasEvent(Req req) {
-		return false; // FIXME
+	public static String getCommand(Req req) {
+		return isPostReq(req) ? (String) req.data("_cmd", null) : null;
 	}
 
 }