Fix area select regression

[farmaazon]

Pull Request Description

Fixes #9182

Now we are careful when to handle events - before or after updating intersected set.

Added general E2E and detailed unit tests for selecting.

Also discovered, that sometimes the test are running while nodes are not yet in right positions. Added an instruction ensuring the position is right.

Important Notes

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• [ ] Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.