JS: provide a scroll pane for runtime error messages
JS: provide a scroll pane for runtime error messages

Required for long or multi-line expressions.

Signed-off-by: Harry King <409587b9e6671aa0763646191d292852dc49a658@gmail.com>

jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim