Rich textboxes are not properly displaying in windows 7

Question

Hi All,
 
In our C# application, we have to create more than 2000 richtextboxes dynamically and we should display them in seven tabs with two columns and we need to fill the data from an excel sheet.we are creating them tabwise and then columnwise. (Its the previous design, so we are proceeding in this way only)
 
The application is working fine with Windows XP. when we run the same application in Windows 7, In the Seventh tab some last rows are not displaying properly. They are overlapping with the previous textboxes. Not all the textboxes are displaying. Also, the last text box(which is not actually last to display), which is last displayed is coming with more than expected vertical gap. when the code is debugged, the Y location value for the textboxes is coming fine but the same is not reflecting in the form .
 
Thanks in Advance.