When we switch to Real Allocation Work screen, show data for all resources

When we switch to Real Allocation Work screen, no resources are selected in the Resource drop-down list.

Then the display remains blank, as shown below:


But this state is equivalent to not selecting any particular resources. (or, in other words, selecting all resources)
Therefore ProjeQtor should show Real Work Allocated to all resources.

In other words, the screen shows the real work done for the whole project in a single screen.
This is useful in understanding how work is progressing.