Userform locks up Excel
 

I have a project which uses a userform to control the user's input.
Among other controls, the form has 5 ComboBoxs.

When the form is populated in it's tab order, all is fine. However,
when the user's order is random, or revisits a previous entry to choose
another selection, or excesive scrolling of the combobox selections
occur, excel locks ups completely.

Each combo box is governed by a seperate table within the spreadsheet. Each
table is given a named range. The named range is attached to the combo box
object's property rowsource.


Most of the governing table's are static and one can be added to by the
user.

This is my first foray into VBA. My project works as intended, except
for this anomally. This is the question I am pondering. Is it a problem
with my code, or is the Excel userform this ficle?