diff --git a/public/src/js/utils/observable-numeric.js b/public/src/js/utils/observable-numeric.js
index 44a48dc6b3..1cfae9a563 100644
--- a/public/src/js/utils/observable-numeric.js
+++ b/public/src/js/utils/observable-numeric.js
@@ -8,7 +8,7 @@ export default function(initialValue) {
         },
         write(newValue) {
             var parsedValue = parseFloat(newValue);
-            actual(isNaN(parsedValue) ? newValue : parsedValue);
+            actual(isNaN(parsedValue) ? newValue : Math.abs(parsedValue));
         }
     });
 }