Follow Custom Action position on the Custom Actions window when changing it's order. Also, add support to Drag/Drop custom actions to change their order.

Version information

Thunar 4.18.4 Linux Mint 22

In the Custom Actions window, the users can use the up arrow button or the down arrow button to change a custom action position in the list, but if the user has more custom actions than the ones that are able to show on screen (i.e., if the user has to move the vertical scroll bar to see all the custom actions on the list), when the user clicks enough times on the up or down arrow to move a custom action, the screen doesn't scroll automatically to follow the custom action being moved. Please make the scroll to follow automatically a moved custom action when clicking the up or down arrow buttons. Also it would be very helpful, to be able to drag/drop custom actions to alter their order.

I have a lot of custom actions, and I mean a lot, and this change would be very helpful to add even more custom actions.

Thanks.