Add a 'Close Display' action

[rjwills28]

I looked into adding a dedicated 'close display' action that can be used in ActionButtons. This is following my request in #3384.

As I explain in that issue, it is nice to have some redundancy in screens and so offer the user multiple ways to close the display, i.e. in addition to the 'x' at the top of the display/window. Note, that as also explained in that issue, this isn't always an option if you have 'Always show tabs' disabled and you are using split windows.

This is a simple action that just closes the current display.

Please let me know what you think?

[rjwills28]

Would it be possible to get some feedback on this new feature?

[rjwills28]

I have checked that all resources are tidied up by this new action to close a display and I can confirm that the method I call to close the display DockItemRepresentation.closeWindow(...):

phoebus/app/display/runtime/src/main/java/org/csstudio/display/builder/runtime/app/DockItemRepresentation.java

Line 146 in 09b7db2

public void closeWindow(final DisplayModel model) throws Exception

calls DockItem.prepareToClose():

phoebus/app/display/runtime/src/main/java/org/csstudio/display/builder/runtime/app/DockItemRepresentation.java

Line 155 in 09b7db2

instance.getDockItem().prepareToClose();

which performs checks to make sure that it is OK to closer the display:

phoebus/core/ui/src/main/java/org/phoebus/ui/docking/DockItem.java

Line 672 in 09b7db2

public boolean prepareToClose() throws Exception

This is the same method called when you click the cross on the top of a display, therefore I conclude that resources are cleaned up in the same way.

I have also used the PV List app in Phoebus to confirm that when you close a display using the new action in an action button, the connections to the PVs are closed and the PV List shows that no PVs are in use.

[shroffk]

@rjwills28 thank you for double checking