Workflow Form does not show picklist with show 2 lists = true

There is a Request Form with a PickList that should only show up after a
'onRemove' event triggered by another field. After an initial field.hide()
though it is never able to successfully do field.show() anymore. 

The starting situation is that the PickList receives a 'onDefault' event and
executes field.hide(). Then, after the user changes a certain value, the
PickList receives an 'onRemove' event and executes field.show(). The
field.hide() works fine, but field.show() does not work anymore.

Two characteristics:
-This only happens to PickLists with 'Show 2 Lists' set to TRUE.
-Request form is started with an 'onRemove' event (instead of 'onDefault')
and afterwards do an 'onDefault' and another 'onRemove' event the whole
PickList works fine (i.e. it shows, hides and shows again). So it only seems to
happen when the starting situation is field.hide().

As a workaround for pick list controls that show 2 columns, one must include
the onload event on the pick list control itself and execute a field.hide()
method.

This will force the JUICE control to execute and be available at the client
side just like the pick list controls with only 1 column do. Basically, the
control must be rendered before it can be hidden.