Fixed stationary event handler editor window

[Patrykb0802]

Expected Behavior
Changing the behavior of the event handler edit form so that it is always visible to the user, regardless of the number of event handlers, meaning it is pinned and moves with the scroll.

Actual Behavior
Regardless of the number of event handlers, the edit form for a given handler is pinned to the very top of the page, so if there are more event handlers, it is not visible to the user, the user must click edit for the given event handler and scroll to the very top of the page, which is cumbersome.

Solution
A similar behavior is present on the Edit Data Source page for point edit forms.

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Problem description:
When using bigger configuration ( >2000 data points), at event handler view when trying to edit event handlers, the editing window is stationary, after scrolling down and choosing suitable event you have to scroll back up to edit it.
Describe the solution you'd like
Appropriate solution would be to "glue" event handler editing window to top border of browser window same as in data point/source view. That will greatly improve ergonomics.