Why do controls reposition when I drop them on my form?

If you drag a web control from the Visual Studio Toolbox and drop it inside a table cell and it repositions to 0,0, it may be due to your Visual Studio positioning options.

To check the positioning options, select Tools | Options from the Visual Studio menu, then check the settings under HTML Designer | CSS Positioning. To stop repositioning from occurring, uncheck the option Change positioning to the following for controls added using the Toolbox, paste, or drag and drop.