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Creating a compound window and using it as the content of the scroll pane is not a real solution. Theoretically, I might be possible that upon scrolling, the content of this compound window be adjusted so that the header parts remain fixed (always shown). However, that doesn't really seem to be a reliable, bulletproof solution, so I had to consider other approaches. Soon I turned to the GridPane (javafx.scene.layout.GridPane). It lays out its children in a Grid, by using rows and columns. The width of the columns and the height of the rows might differ from each other. It is easy to achieve that all components within the same column be sized to have the same width, and within the same row to have the same height. In fact, that's the default behaviour. So I might have the following layout of this GridPane:
| Header of the | Row Header | The Column Header - that is, the Timeline view | Header of the Row Footer | Empty |
| The Row Header - that is, the resources the activities are assigned to. | The activities and the relations between the activities. The activities start at a specific point of time, end later, and they belong to resources. | The Row Footer - that is, the resources the activities are assigned to. | Main vertical scroll bar | |
| Horitonzal scroll bar of the Row Header | Main horizontal scroll bar | Horizontal scroll bar of the Row Footer | Empty |
Therefore, the resources might be either repeated, or being able to display different set of information on the right side - that's the "Row Footer". It is also shown that the resource view might be wider than the available space - hence the horizontal scroll bars for the row header and footer. This is possible, because the optional header of the row header or the header of the row footer are both supposed to have the same width than their corresponding resource view. However, the height of the timeline view must be fixed, and it cannot be scrolled - that's because the height of the header's and footer's header might have different height than the timeline view has.
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