All my Icons display as blank boxes, how do I fix this?

ide H5
1

H5 can manage icons in multiple ways
The default is to use PNG instead of Icons, it translates the icon name to .ico.png
INSERT.ICO becomes INSERT.ICO.PNG

Icon batch conversion program Diego posted on the newsgroup 21/10/2016, uploaded to Github for convenience:

If you prefer to use the old icons you have to call the
GlobalFiles.SetIconsSupport(1)
SoftVelocity recomend the use of PNG icons, then you can modernise the images changing only the web ones.