Resizing the search and select prompt control
You can specify the size for the Search & select prompt control in interactive reports.
To change the size, use the Size & overflow property that is now available also for the Search & select prompt, in interactive reports only.

The minimum width and height for the Search & select prompt control depend on the Multi-select property that can be either turned on or turned off for this control. If the Multi-select property is turned on, the minimum size is 550 pixels (width) by 428 pixels (height), and the two lists in the prompt control have equal widths. If the Multi-select property is turned off, the minimum size is 250 pixels (width) by 428 pixels (height).
If a report that includes custom-sized Search & select prompt controls is converted to a classic report, the report author must clear the size for the applicable controls.
For more information, see Resizing the search and select prompt control.