*  4. Intuitive cross-fading (suggested by Matt Brubeck )  
 
One of the most common operations people want to do when mixing audio is to smoothly transition between two sound clips. This is commonly called a cross-fade. This operation is technically possible in Audacity now, but it is very clunky, requiring multiple steps and no editability short of undoing the actions and starting again. We are looking for someone to implement a clean, intuitive, nondestructive cross-fade for Audacity. Audacity already has all of the infrastructure necessary to support implementing this operation nondestructively and we already have a clear plan for how it should work. The following webpage has a mockup of what we think the GUI might look like:
 
http://limpet.net/mbrubeck/temp/cross-fade/
 
This feature, while seemingly small, would represent a huge boost in usability for Audacity. This feature is intimately related to several other UI enhancements that we have proposed: for example, one element of this proposed GUI is that clips "stick" to each other or "snap" into place when you push them together. Such a snap-to behavior would be great in several other circumstances, for example having a track stick to t=0, or to a point that lines up with another track.
 
Early spinoffs from this work:
 
    * Ability for all effects to be faded in/out automatically. This can avoid clicks in some circumstances.
    * Label tracks to stick to the track above, so that they edit together.