When TotalView first displays a Variable Window, the value of the Expression field contains a variable, element, or expression. The exact contents depend upon what you dove on or what was entered in a View > Lookup Variable command.

By changing this field’s text, you can change what is displayed. For example, if the expression contained the variable my_var, you could change this to my_var.struct1.substruct1[3].

As the name of this field implies, you can type an expression in this field. For example, you could type either i+3 or my_var[i+3]. You cannot, however, enter an expression that contains a function call or an expression that has a side-effect. For example, you could not enter my_var[i++].