combo box items apear in body of tab intermittantly

Our xform screen is made up of tabs.
Each tab has a combo box at the top of the tab body
On intial display the combo box items may appear written accross the top of the tab body
Tabbing around seems to make it go away.
Have seen this since > 1.5.7.1006

Another similar display funniness is on inital load of the form.
I have a submission element that contains a message element with ev:event="xforms-submit-error"
The contents of the message element appears in the window before the xform is fully rendered.
I have also tried placing the message inside an action element - same result.
Have seen this 'forever'