In extended, tooltips may be placed on the chart buttons to help the player understand them. On the other hand, standard does not have them.
There used to be a tooltip on the chart button in haltinfo, but it seems to have disappeared when scalable gui was incorporated from the standard.
I apologize for my oversight. (´・ω・｀)
Pull request #477 will fix it. Please confirm.
Confirmed fixed - thank you for this.