changine all note lengths

Been wondering how to do this and never quite been able to do what I thought should be easy but how do I set all notes to be the same length. Lets say in this scenario I have in my ride cymbals (several hundred notes) and some are stupidly long and others quite short.
I want to be able to select all the ride cybal notes by clicking on the a prv key and have a length filter that will set them all to the same length.
 
I tried the event filter but that only finds notes of a minimum/maximum value.
This should be so easy and obvious and perhaps it is but it's eluded me for years.
Like I said, some of the notes (ride cymbal) are a duration of 5 and others are at 15:032.
I would like them all to be around the 20 mark.
Anyone know how to set them all to the same length in one go?
Should be a doddle right?
 
Steve

1. Select notes.
2. Enter the duration into the Event Inspector module of the Control Bar.

This ends today's tutorial. 

Thank you people.
I used Brundles method and it worked a treat.
I don't do much midi editing but was digging up some old songs and obviously I don't make those kind of mistakes these days but these old tracks were all over the place.
Much appreciated.

Steve