Hi Tim,
Thanks for the reply.
Nothing happens, the shortcode is shown as if it was not processed.
For instance, if I put this shortcode in a text widget
[googlemaps https://maps.google.com.br/maps/ms?msa=0&msid=208649434188009166040.0004c11dc9ea7f1cc408e&ie=UTF8&t=m&ll=-29.166794,-51.181784&spn=0.023982,0.016136&z=14&output=embed&w=188&h=320]
the site visitors will see the shortcode unprocessed instead of the map
E.g. it does not produces the Google Maps iframe
<div class="googlemaps"><iframe width="425" height="350" frameborder="0" scrolling="no" marginheight="0" marginwidth="0" src="https://maps.google.com.br/maps/ms?msa=0&msid=208649434188009166040.0004c11dc9ea7f1cc408e&ie=UTF8&t=m&ll=-29.166794,-51.181784&spn=0.023982,0.016136&z=14&output=embed&w=188&h=320"></iframe><br /><small><a href="https://maps.google.com.br/maps/ms?msa=0&msid=208649434188009166040.0004c11dc9ea7f1cc408e&ie=UTF8&t=m&ll=-29.166794,-51.181784&spn=0.023982,0.016136&z=14&source=embed&w=188&h=320" style="text-align:left">View Larger Map</a></small></div>