Hey folks, bit late to the party here but I pulled my Libretto out and tried it, exact same thing for me both in and out of the large dock (the one that adds another PCMCIA slot).
Oh cool you have one of those docks, I personally have been wanting to get one but I can't even find one of the lesser ones let alone the superior one, at least not since 6 years ago. Also to respond to your response regarding this situation, firstly you are not late to the party everyone is welcome, especially if they have something to add to the situation. Secondly, thanks to your observation of this phenomenon happening to you as well even when using the dock, makes me think that my theory with how the power management is dealt with is correct. My theory is that because of the type of batteries that these machines have, Toshiba decided to implement a way for the devices to be used while plugged in and not damage the batteries by over charging them. So their solution to this problem was to simply make it so that the Libretto wouldn't charge when it was in use and on wall power, but would charge when it wasn't in use and connected to wall power, meaning that it has been made to prioritise the use of the wall power rather than the use of the battery. I haven't check, and I am too scared to try it
, but I have a feeling that the motherboard might have a power detection and regulation circuit that is used to tell the system to prioritise the use of wall power over the use of the battery, and to only charge the battery when the sub-notebook is not in use. If that makes sense then that is good, if not please let me know and I will try to simplify it again for you, and as a heads up I am not saying that anyone who cont understand what I have written is stupid, I am just saying that I have a tendency to sometimes just go round in circles and also sometimes make thing more complicated than they need to be. So just let me know and I will try to simplify that again if you want me to.
I hope this helps, sorry for it being so long, I just needed to clear my thoughts out about this, and see if my theory holds any water or not.