Hello Frank,

Would mind to guide me how to do it? E.g in video recording. This approach can avoid missunderstanding when replicate your issue.
Also, Please let me know if it is reproducable in our sample (which sample) or not.

Default behaviour
WebGrid would ignore the other process when the current process has not finished yet. 
It will show dialog box about that. So, I need to know in detail how you replicate the issue.

Regards,
Handy

Please see the picture and the Demo code.
Environment:VS2008+IE8.0

Hello Frank,

The project is missing product.mdb. Also, What is the step by step to replicate the issue after I could run the project? Thank you.

Regards,
Handy

this is product.mdb

Hello Frank,

I could not run it directly because your WebGridColumn, DataMember and database field are not showing correct chinese character in your sample.

I figured out three columns (based on your screenshots), but I am missing your last columns.

Please see the snippet tags below and let me know what is your last column.

Your tag:

   <ISWebGrid:WebGridColumn Caption="vouid" DataMember="vouid" DataType="System.Int32"
   Name="vouid">
   </ISWebGrid:WebGridColumn>
   <ISWebGrid:WebGridColumn Caption="ÉÌÆ·Ãû³Æ" DataMember="ÉÌÆ·Ãû³Æ" Name="ÉÌÆ·Ãû³Æ">
   </ISWebGrid:WebGridColumn>
   <ISWebGrid:WebGridColumn Caption="±¸×¢" DataMember="±¸×¢" Name="±¸×¢">
   </ISWebGrid:WebGridColumn>
   <ISWebGrid:WebGridColumn Caption="ÐÔ±ð" DataMember="°ü×°μ¥Î»" Name="°ü×°μ¥Î»" EditType="WebComboNET" WebComboID="WebCombo1">
            <ValueList DataTextField="ÐÔ±ð" DataValueField="Öμ">
            </ValueList>
   </ISWebGrid:WebGridColumn>

I only figured out:

   <ISWebGrid:WebGridColumn Caption="vouid" DataMember="vouid" DataType="System.Int32"
   Name="vouid" Width="100px">
   </ISWebGrid:WebGridColumn>
   <ISWebGrid:WebGridColumn Caption="商品名称" DataMember="商品名称" Name="商品名称" Width="100px">
   <ISWebGrid:WebGridColumn Caption="备注" DataMember="备注" Name="备注" Width="100px">
   </ISWebGrid:WebGridColumn>

The same issue also persits in your WebCombo. I need to know the correct character. I am sorry for the inconvinience.

Regards,
Handy

Anyway,once I use custom InsertDeleteUpdate,I will  meet the problem.So I use your Default way!