Issue #47 was closed, but I don't think the explanation given was satisfactory

[acortesc]

The issue mentioned that, when the dropdown was set to render aligned to the top and left of the control and there was no room below the control to properly render it, it was not automatically aligning to the bottom. Something similar could happen if the control was displayed near the right border of the window (rare, but possible).

The alternative for which it was closed stated that you could set it to align to the bottom, but this would still be a static alignment. The alignment should vary depending on the size available near the control. The default valign should only be used if there is room to properly render the control, and it should be ignored if there isn't.

This behaviour is the same as the native select control in HTML, and it is both useful, comfortable and what people expect.