ExpandoPane isHorizontal logic reversed?

[Sam Foster]

ExpandoPanes? have a _isHorizontal property that's used to determine which axis the pane should expand/collapse along etc. isHorizontal is set thusly:

this._isHorizontal = !/top|bottom/.test(this.region);

to me this is reversed. Top and bottom region panes /are/ horizontal - their splitters will be horizontal. Expansion is along the 'y' or vertical axis - but the property name is ambiguous at best if that's the intention.

Proposal: reverse the logic:

this._isHorizontal = /top|bottom/.test(this.region);

.. or, rename the property to _isHorizontalAxis or something.

Its private so while this might screw some people who'd extended from ExpandoPane?, its not strictly a public api change? (also ExpandoPane? is marked as experimental still)

[dante]

(In [12933]) fixes #6099 - logic private change of the meaning of _isHorizontal (the pane extends horizontally, whereas it was "the direction of the splitter movement" before)