diff --git a/assets/css/global.css b/assets/css/global.css
index e226c6c..f7264ba 100644
--- a/assets/css/global.css
+++ b/assets/css/global.css
@@ -33,6 +33,9 @@ div.transfer_menu {
 	height: 100%;
 	border: 2px solid orange;
 }
+div.transfer_menu input:invalid {
+	background-color: #faa;
+}
 
 div.plate_container {
 	border: 2px dashed purple;
diff --git a/src/components/transfer_menu.rs b/src/components/transfer_menu.rs
index b3d0858..eb3b63d 100644
--- a/src/components/transfer_menu.rs
+++ b/src/components/transfer_menu.rs
@@ -29,7 +29,9 @@ pub fn TransferMenu() -> Html {
                         interleave_x: state.interleave_x,
                         interleave_y: state.interleave_y
                     });
-                    log::debug!("{:?}", dispatch.get());
+                    input.set_custom_validity("");
+                } else {
+                    input.set_custom_validity("Invalid region.")
                 }
             }
         })
@@ -50,7 +52,9 @@ pub fn TransferMenu() -> Html {
                         interleave_x: state.interleave_x,
                         interleave_y: state.interleave_y
                     });
-                    log::debug!("{:?}", dispatch.get());
+                    input.set_custom_validity("");
+                } else {
+                    input.set_custom_validity("Invalid region.")
                 }
             }
         })