In Writer there are several ways that the Sidebar Panel can be hidden or shown. One of those ways is to use the keyboard shortcut Ctrl+F5 to toggle Hide/Show. Another way is to use the Panel Hide/Show button. However, there is what I would think is anomalous behaviour if these two methods are mixed as follows:

1. Hide the Panel using the Hide/Show button. This retracts the entire Panel with exception that the Hide/Show button is still visible.

2. Now lets say you want to open the Panel again but this time you use the Ctrl+F5 keyboard shortcut to show the Panel. What actually happens is as follows:

(a) The first press of Ctrl+F5 causes the Panel to fully retract i.e. the Panel Hide/Show button is retracted.

(b) You think something is wrong as you wanted to show the Panel so you press Ctrl+F5 a second time and then the Panel extends outwards and is shown again (which was what you were trying to achieve at the outset).

So it would seem that the Ctrl+F5 shortcut interprets a Panel hidden via the Panel Hide/Show button as being a Panel that is not in fact hidden at all. So, in that instance the first Ctrl+F5 keypress hides the Panel.

I don't think things should be happening in that way. Ctrl+F5 routine should recognise when the panel has already been hidden by the Panel Hide/Show button and should show the full Panel on the first Ctrl+F5 keypress. I would regard that as 'expected behaviour'.

The same 'issue' occurs in at least Calc, Draw and Impress.