Here is a technique you can use to resize a response window or userobject as needed. It makes use of the GetWindowLong and SetWindowLong Windows API methods. The oldest reference I found to this is from Eric Aling back in 2000.
From the 12.5 Powerbuilder Help on this method: Converts pixels to PowerBuilder units. Because pixels are not usually square, you also specify whether you are converting the pixels' horizontal or vertical measurement.