improved calculation fields

app/imports/ui/properties/forms/shared/ComputedField.vue

@@ -2,9 +2,17 @@
   <div class="computed-field">
     <text-field
       :value="model.calculation"
+      :rows="1"
       v-bind="$attrs"
       @change="(value, ack) => $emit('change', {path: ['calculation'], value, ack})"
-    />
+    >
+      <template
+        v-if="model.value !== undefined || model.value !== null"
+        #value
+      >
+        {{ model.value }}
+      </template>
+    </text-field>
     <calculation-error-list :errors="model.errors" />
   </div>
 </template>
@@ -19,7 +27,7 @@ export default {
   props: {
     model: {
       type: Object,
-      default: () => {},
+      default: () => ({}),
     },
   },
 }