I'm using VWG v6.2.0a (unstable), WinXP Professional SP3, IIS v.5.1, Visual Studio 2005 SP1 (v.8.0.50727.762, SP.050727-7600), MS IE v.6.0.2900.5512, FireFox v.3.0.
Source code of project is modified snippet CheckedCombobox. The modification is replacing string "public class ComboBoxTreeTreeView : TreeView" by "public class ComboBoxTreeTreeView : DataGridView" (in ComboBoxTree.cs) and removing code that works with TreeView events and methods (in ComboBoxTree.cs and Form1.cs). A can send it for you, but I don't know address.
When I click on combobox button, MS IE shows error message described at my previous message. FireFox says nothing, and shows GridDataView. But grid looks not very well - it has rectangle from left top corner of client area of browser to right bottom corner of grid.