Office 2007 Excel Addin - WPF ComboBox Collapses when Expanded RRS feed

  • Question

  • Hi,
    In my Excel Application level Addin I have a WPF window ( contains WPF combobox ) which opens as a Modeless dialog on a Ribbon Button click event.
    The dropdown list of a ComboBox control disappears when I release the mouse left button on the dropdown  arrow.
    If i opened the wpf window as a Modal dialog it works normally.
    Using winspector spy (tool to monitor window messages) i noticed that the WM_CAPTURECHANGED Message fires continuously when the combobox expands and immediately closes. if it was a modal dialog it fired only once
    The Addin was developed using VS2008 SP1, Framework3.5 SP1, Office 2007/2010
    This problem occurs only for Excel Addin, the same code works good for Word, PowerPoint, Outlook

    Please help me in fixing this issue.
    Wednesday, May 18, 2011 1:07 PM