slider widget '-' not recognized as float sign if no 0 before decimal

[MacroMachines]

Was on the shapes page http://thebookofshaders.com/07/
editing the polar curve design just above the bottom triangle, uncommented the line
"// f = smoothstep(-.5,1., cos(a*10.))*0.2+0.5;"
and edited the "-.5" with the slider widget, got an error when it went positive and back negative again, the slider widget added another "-" sign and a 0 before the '-.5' resulting in '--0.5'

also side note - japanese dude is making a interesting webgl editor using this repo called 'shaderninja'
http://www.shallway.ninja/shaderninja_editor

[alijaya]

I think it has been resolved? :-?... I can't reproduce it