When customizing a List block you have access to two means of controlling the properties of a column. The first is by using the create script for the column. See the article "Using Create Script in GridColumns".
The second technique depends on using clientside code that has been delivered to the screen through the Custom Content box. This technique can be used within the hosted environment (sagecrm.com).
For example, to change the hyperlink on the final comm_status column on the communicationlist block so that when it is clicked it will pop open in a new window we could use:
//firefox way of binding an event
window.addEventListener("load", newWindow, false)
//IE exclusive method for binding an event
var arrayTags = document.getElementsByTagName("A");
arrayTags[i].target = "newWindow";
This code looks for the hyperlink that calls the Action 364 (which would open the communication in edit mode and set the status to complete) and sets the target of the href to be 'newWindow'.
Another example of example of changing the properties of columns in a list is given in the article "Making tooltips work in Firefox, Chrome, Safari, Opera et al...".