Q: Selenium driver findElement by.xpath unable to access the last column in the table. Selenium RC code worked well Selenium driver: The last column in the table  (th[10]) is not  accessed by driver.findElement By.xpath:
driver.findElement(By.xpath("//*[@id='collapseOne_DMTS']/div/table/thead/tr[1]/th[10]")); 

I used the code to get the last (10th) element in the table (0-10). 
All other elements including element 9 are successfully retrieved by the code.
The code worked fine with Selenium RC:
selenium.getText("xpath=//*[@id='collapseOne_DMTS']/div/table/tbody/tr["+(i+1)+"]/td[10]");

- all elements of the table  were  accessed successfully. 

A: Do not concatenate selectors. Use collections. 
List<WebElement> columns = webDriver.FindElements(By.xpath("//*@id='collapseOne_DMTS']/div/table/thead/tr[1]/th"))

