Silk bug workaround for control not responding error
In some cases Silk throws a CONTROL NOT RESPONDING ERROR when a user is trying select an item from an HtmlListBox. Here is a workaround for this Silk Bug:

Agent.SetOption(OPT_VERIFY_RESPONDING, FALSE); //ignore control is not reponding error
BrowserPage.HtmlListBox.Select(sItem); //incorrectly selects the item before the desired and specified item in the list (Silk bug)
int iIndex = BrowserPage.HtmlListBox.GetSelIndex(); //Get the index of the item Silk erroneously selected
BrowserPage.HtmlListBox.Select(iIndex+2); //add 2 to the iIndex and select the item via the item index. This will correctly select the original, desired item from the list.

Html Table trouble and lack of object recognition workaround
Use the ShowBorderlessTables domex.ini setting to adjust what Silk recognizes in your web page

ShowBorderlessTables=.0 //ignores tables but recognizes links and html objects within tables
ShowBorderlessTables=.9 //shows nested table but may not recognize some items within tables

You can adjust this value in the domex.ini file found in your SilkTest\extend directory. This setting defaults to .5. I find the .0 setting seems to recognize html content much better.

HtmlCheckBox and HtmlRadioList dynamic text item content seen as {#1,#2,#3} workaround
Silk sometimes seems dynamic HtmlRadioList and HtmlCheckBox content as {#1, #2 #3} instead of seeing the actual text caption of the list item.
If you have dynamic content in your webpage you need to be able to pinpoint items by their text caption. You can do this by
using the HtmlText object and then use negative coordinates to check the item. you can also use Desktop.GetFocus() to return the the actual object class and use the specific class methods at that point.
For example:

window w = BrowserPage.HtmlText("Some radio option Text"); //The caption of first item listed in a HtmlRadioList
w.Click(1,-30,5); //Use negative coordinates to click the actual radio option.
window wObj = Desktop.GetFocus(); //This will return the window for the radio option or checkbox item. If wObj is a HtmlCheckBox you could then issue a wObj.Uncheck() command.