test better detail combined view

app/UI/VmUpdate/Sections/Qemu/AdditionalDiskSection.php

@@ -32,7 +32,7 @@ class AdditionalDiskSection extends BaseSection implements ClientArea
         $rangeField->setMinValue($diskSize);
         $rangeField->setDefaultValue($diskSize);
         if ($this->configuration()->serverDiskSize->max > ($this->resourceManager->disk()->free())) {
-            $rangeField->setMaxValue($this->resourceManager->disk()->free() + $diskSize);
+            $rangeField->setMaxValue($this->resourceManager->disk()->free());
         } else {
             $rangeField->setMaxValue($this->configuration()->serverDiskSize->max);
         }