Hi Brian,

> style="width:100%;"

This one is standard HTML - it means to make the element take up the entire width of its container. On some kinds of elements like a table if you don't set width=100% it can kind of shrink down to be smaller than that if it goes down to just hug the size of the text inside of it. For some kinds of things that would not be good - like imagine the "Done" and "Cancel" buttons if they were like that.


> style="width:3em;

This one is also standard HTML - ems are a measurement unit that is relative to the current font, so that's like saying make it the width of 3 characters of the current font size. See here for more info on CSS units: http://w3schools.com/cssref/css_units.asp


> style="persist:true;"

That one is a MoI-specific attribute - that sets whether a control in the command UI will remember its value on the next run of the command or not - some controls default to persisting the value and if I remember right some controls like text input fields default to not persisting it, but the default persist value can be overwritten by assigning that style property to the specific element.

If an control in the command UI is set to persist then its value is recorded when the command ends, and the next time that command starts up it will get initialized with that value.

- Michael