I'm not sure about what is exactly the error, but I can describe the problem.
I have the next design:
I can have the TWebDataSource component assigned to all the TWebDBEdit controls on the left side of the form OR I can have the TWebDataSource assigned to the TWebDBGrid, but If I assign the TWebDataSource to both types of control at the same time, at runtime the whole program hangs when I create this form.
In the previous test, I positioned the TWebDBGrid in another TWebTabSheet component. In this case, the program runs, but I can't edit or do any other operation over the TWebClientDataset. When I try it, the whole program hangs, too.
There is no necessary source code for this failure.
I've just tried the next changes. I've added a new TWebClientDataSet and a new TWebDataSource. The TWebClientDataSet points to the same existing TWebClientConnection.
The problem is the same. Only by opening the form at runtime does the program hang.
I finally tried creating a second TWebClientConnection. In this case I have the three component group, TWebClientConnection, TWebClientDataSet and TWebDataSource, duplicated. One serves the Edition components, and the second serves the TWebDBGrid components.
The logic dictates that this will work, but.... hangs, too.
I suppose you will need to create a demo application or send your application so we can investigate this here. Without actual code or project it's not clear how to reproduce this here.
No code is needed. Yo only need to drop the components on a form.
The problem is that for create a demo of this type, I need to create too the Backend, true?
Try to do as described, and you are going to see the problem immediately.
If you want, I can make a Video but I don't know if I can upload it here o I need to put it on youtube.
My recomendation is to tray to reprofuce in your house the problem.
You don't need the visual components. Only the DB components.
Please press F12 and see if there are console errors.
I took the demo Demo\Basics\DataSet, added a TWebDBGrid and connected it to the WebDataSource on the form (that is also connected to several TWebDBEdits) and I cannot see any problem with this setup.