The next update MathStudio v5.3 will make a small change in syntax for matrices. The following examples will now return a matrix instead of a list.

A=[[1,2,3],[4,5,6],[7,8,9]]
A(1,2:3)
// Output: [[2, 3]]

A=[[1,2,3],[4,5,6],[7,8,9]]
A(1,all)
// Output: [[1, 2, 3]]

You can also turn off this behavior using the command function to turn off matrix detection.
http://www.mathstudio.net/manual/Command