Device/event scroll bars don't work correctly during test execution

[adamj537]

Describe the bug
During test execution, events tab keeps jumping back to the starting position. This is likely also true of the devices tab.

To Reproduce
Steps to reproduce the behavior:

1. Open or create a test that has enough events that the "Events" tab shows a scroll bar. Ideally, the list of events should be several times longer than the length of the events tab. (If equipment is not available, create one or more devices of type "Simulator" and use them in the events).
2. Click on "Start" to begin the test.
3. Navigate to the "Events" tab.
4. As the test is executing, scroll through the list of events. The scroll bar will periodically reset if the user is not quick enough.

Expected behavior
User should be able to scroll up and down events and devices during test execution smoothly.

Environment (please complete the following information):

• OS: Windows 7 Pro
• Equipment: four Cole Parmer Mass Flow Controllers