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You cannot assign unique DOM Ids in interfaces. For stable UI automation, use FitNesse for Appian, Cucumber for Appian, or Appian Selenium API, instead of raw Selenium identifiers.
If this is for testing purposes, use one of the test framework plugins Appian provides.
You can not use IDs, but you can create a generic xpath, identify a label first, then navigate to the element(Input, TextBox, Radio button, Dropdowns and others). We use xpaths in our C# Framework wtih Selenium WebDriver.