I have a request by a customer that they wish to have square alarms on their custom dashboard. To my knowledge this isn't fully possible unless you use the slider. Unfortunetly these are to function are the normal circular alarms.
This customer has stated they have seen this done before. I have requested them to provide a screenshot of the exact dashboard, but they "do not remember" where they originally saw this.
by creating a 1x1 transparent gif and uploading it to the UMP than by changing all the alarm images to this 1x1 image.
The UMP will automatically mask based on the color of the alarm.
1x1 transparent pixel is attached.