title: Combobox governing subform possibly updating tables
body: <p>I have a form, the form is bound to a query which returns only one field.  On that form is one combo box, bound to the field from the query, a subform object and some other unimportant stuff.  The Master-Child relationship between the Form and Subform is set to that same field.  The intent is that dropping down the combo box allows me to add information on the subform pertaining to that record in the combobox (it's a list of classes in a school, for context).  This is done through a form and subform as I have various different tasks that need to be done for each class - the intent is to be able to select a class on the main form and then use command buttons on it to select which subform is opened depending on which task I wish to perform.</p>
  
  <p>However, the Combo box appears to be trying to update a table - I'm not sure which one as the error message isn't specific:</p>
  
  <blockquote>
    <p>The changes you requested to the table were not successful because
    they would create duplicate values in the index, primary key or
    relationship.  Change the data in the field or fields that contain
    duplicate data, remove the index or redefine the index to allow
    duplicate values and try again</p>
  </blockquote>
  
  <p>appears if I select any value other than the first one from the combo box and then click in the first text box on the subform.  However, I can click in the subform with the first entry in the combo box selected and add data successfully, I've checked and it is appearing in the underlying tables.</p>
  
  <p>It seems to me, as a relative novice in Access, that the combo box is attempting to update the underlying data source when it is changed, though it has no macros.  I would assume there are items in the properties of the form or the combobox that prevent that from happening but I can't find them.  That is just a guess as to what's happening, though, and I could be wrong.</p>
  
  <p>It's possible that this is related to <a href="https://stackoverflow.com/questions/9353511/how-do-i-prevent-clicks-on-a-subform-causing-updates-on-the-main-form">this question</a> but I could be mistaken there as well.  Regardless, the Form shouldn't be able to update/edit/add records but if I set Allow Edits in its properties to "No" I am unable to actually select a value from the combobox - I have set the other "Allow" properties to "No" without a problem.</p>