In JavaFX, tab functionality is handled by two classes javafx.scene.control.TabPane, com.sun.javafx.scene.control.skin.TabPaneSkin (the former handling the selection logic and events, the latter responsible for painting).

Currently, the user is required to perform a mouse click in order to select a tab. That is, the tab is only selected once the user has let go of the mouse button. This results in the tab UI feeling less "snappy". It is also somewhat strange to allow the user to press the mouse on a tab (header area), then move the mouse outside of the header area, release the mouse -- and see the tab in the "old" location be selected.

The key implementation change is that the selection handling code should be fired from a mouse press (in the relevant area), rather than a click or action event.