The braces were removed from these if statements, making the code more compact but potentially less maintainable. While this follows some coding styles, it can increase the risk of bugs if additional statements are later added without re-adding braces. Consider whether consistency with the project's style guide is maintained.

The _comboboxDuration field is marked as nullable (ComboBox?), but it's initialized in the constructor on line 62 and should never be null during the object's lifetime. Making it nullable adds unnecessary null-checking overhead (lines 94, 119) without providing value. Consider making this field non-nullable to better reflect its actual behavior.

The original code used ObjectDisposedException.ThrowIf to throw an exception if the object was already disposed. The new code silently returns early instead. This changes the behavior from failing loudly (which helps catch double-disposal bugs during development) to failing silently. Consider whether this is the desired behavior change, as the original pattern helped identify misuse of disposed objects. If the goal is to prevent exceptions, document why silent failure is acceptable in this case.

The null-check for _textboxReason is unnecessary. The field is initialized in the constructor (line 52) and is not nullable, so it will never be null at this point in the Dispose method. This defensive check adds complexity without providing value.

The Okay button now calls Close() instead of Dispose(), but AdminWindow.cs still explicitly calls Dispose() on the _banOrMuteWindow after the okayHandler is executed (lines 481 and 512 in AdminWindow.cs). This creates a double-disposal scenario: Close() is called first (line 82), followed by an explicit Dispose() call. Even though the Dispose() method now checks for _disposed and returns early, this pattern is confusing and could lead to issues if DeleteOnClose is set to true on this window (which would cause automatic disposal on Close()). Consider removing the explicit Dispose() calls in AdminWindow.cs.