To reproduce: 1. On a touchscreen computer, go to http://www.google.com/ 2. Touch the text field to focus it No Input Panel icon appears. The Input Panel icon should appear next to the focused text field
<rdar://problem/6907066>
Note that in step 2, you need to focus the text field by touching the touchscreen, not by using the mouse.
<http://msdn.microsoft.com/en-us/library/ms811573.aspx> has info about how to implement this.
This affects Vista, as well.
Apparently the control over the position of the Tablet Input Panel can be even more fine-grained. See <http://www.code-magazine.com/Article.aspx?quickid=0704142>.