When a user attempts to add a CD-ROM drive and selects an ISO file to upload, the interface still allows them to select an existing ISO or upload a new one. The buttons for these actions should be disabled once an upload has started, and only re-enabled if the user cancels the upload.

Always

1. Navigate to the virtual machine settings.
2. Click "Add CD-ROM drive."
3. Select "Attach ISO file" and choose a local ISO to upload. 

After the upload starts, the "Browse" button and the dropdown for existing ISOs remain active and clickable.

Once the upload begins, the "Browse" button and the existing ISO dropdown should be disabled to prevent the user from selecting another file or ISO simultaneously. They should only become active again if the current upload is canceled.

This behavior can lead to user confusion and potential errors if they try to change the ISO while an upload is in progress.