[24.2] Fixes window manager scrolling and resizing

[guerler]

Minor style fixes for the window manager, slightly increases the size notification icon and allows users to scroll to the bottom of a maximized window. When the window is maximized masthead options do not work, since the center panel remains invisible.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.