second minor bug in wxt legend toggle

[<pl...@pi...>]

Hi,

another oddity.

If I put annotations on a graph using mouse button to mark coords, these 
seem in some way linked to the last plotted line.

If I toggle visibility on the last plotted line the annotations get 
hidden too. Not the case if I toggle any other plot lines using legend 
toggle feature.

since the annotation could be related to any line on the graph this 
seems accidental and unhelpful.

Also , once the last plot line is hidden, no annotations can be made 
(they are not even made "hidden" to reappear later.)

there seems to be an unexpected linkage between the last plot line and 
the annotations.

best regards, Peter.