In left hand side of test cases tab, following sections are there as shown in the below screenshot:

1. Test Suites section
   • All the test suites which are defined in the Project Configuration tab will be shown here. 
   • A test suite is a group of test cases to be executed in sequence. 
   • Select the test suite(s) to filter out the test cases in TC tab main body.
2. Filters applied section
   • Any filters applied will be shown here in this section.
   • Filters can be applied from filter icon in TC tab tool bar.
   • To clear the filter, click on the Reset link available in this section.
     Note: Reset filter doesn't clear the Test Suite filter.
   • Individual filter items can be cleared by clicking on them.
3. Environment section
   • Select the desired environment for test case execution.
   • Environments can be configured from TC tab tool bar >> More Menu >> Global Variables / Environments.
4. Keep variable alive section
   • If checked, then variables' value will stay intact between test runs. 
     • Variables will be initialized only for the first test run from Global Variables. 
     • But once you refresh the page, variables will be cleared and will be initialized again from Global Variables.
   • Otherwise all the variables will be cleared before the next test run.
5. Continous Integration section
   • This section shows a button to copy the current test case list URL.
   • This URL will be directly used in vrunner module for continuous integration purposes.
   • For integrating with Jenkins server, please read this guide post.
6. Quick guide links section
   • It will show you the most used guide links.