UI window not resizable and content wastes too much empty space

[Timur Born]

<p><strong>Actual result:</strong></p>
<p><strong><img src="https://i.imgur.com/2wGBZiV.png" alt="" width="793" height="779" /></strong></p>
<p><span></span></p>
<p><strong>Expected Result:</strong></p>
<p><strong><img src="https://i.imgur.com/hv7BDy0.png" alt="" width="462" height="345" /></strong></p>
<p>Of course, some space and graphics should be used for design, but the current implementation is wasting so much space for literally "nothing" inside a fixed size window. Now we need to scroll for nearly everything.</p>