Notice: this information was written when Microthemer version 2 was current. On Dec 26th, 2014 version 3 was released with a completely new interface. Some of the information may be redundant, but as much of
the functionality remains the same in version 3 we haven't deleted this post.
I am using the trial version of microthemer. I double click on an element and give it a name. I want to edit the dimensions but there are no current dimmensions showing. Does that mean I have to experiment with different widths and heights to find out what I want to set? I think it would be nice to see what they are before I start futzing with it.
In the mean time, you can use firebug for firefox for chrome to get the existing CSS values of elements.