[dmw_ng]

We only very briefly had that around the start of Win95, by the time 98 came around (IIRC) Explorer and definitely IE already had flat toolbar buttons that only had bevels when hovering. I remember fetishizing how clean those new style controls looked (esp IE5ish with its grey-on-grey patterned background texture!) but it definitely broke the consistent interaction idiom you mention

[ptx]

In the case of toolbars though, I think flat buttons were OK given that the toolbar itself can easily be identified as a toolbar and you know that toolbars always contain buttons, so there is no need to identify each individual button as a button. Of course, when other widgets start getting added to the toolbar it's not as clear anymore.