Trying to enter a value in cm first will behave oddly and set as NaN the in field.
The text entries become pseudo-non-editable, i. e. you cannot delete a single character.
Same thing happens for kg and lb pair of text entries.
Works as expected for me in firefox and safari, though not that same version of firefox.
Fixing issue #252
Checking in more fixes for #252
This has been fixed.