Conditional formatting - space for editing rule

The space for writing and editing a formatting rule ("Format values where this formula is true") is way too small for some of my formulas, and it is only possible to move the cursor with the mouse, i.e. the formula cannot be longer that the field in the dialog box unless it is written correctly in the first go.
Is it possible to expand the dialog box so that a long formula can be written and edited in small steps?

NSV