can't select/revert to colourful/3D icons everywhere
I started using new XFCE added to Slackware 14.2+current (and now Slackware 15+current) after using XFCE years on less-powerful PCs, now also on main desktop (KDE is often slow/halting even on cutting-edge hardware) but noticed if I select colurful/3D icons (Oxygen, etc.) it doesn't select/revert those in panel system tray (systray, battery/UPS, clipboard, notifications, volume, etc.) rather than using mid-1900s-style black&white (b&w)/2D icons (Breeze, etc.)
Such icons started for pad/tablet PCs by developers who weren't actually alive or creating professional graphics/software when sometimes monochrome was the only option. That was the case when I was growing up, with monitors, black & white graphics/art like photocopies, cartoons (sometimes more 2D than 3D) etc., but I dislike reliving that. It's not more useful or trendy, but actually less useful, because less recognizable. If someone selects an icon set, it should apply to entire panel/systray.
Normally I'd beta-test my main X window manager (WM) or desktop environment (DE) but several older Slackware users are switching back to older XFCE because same experience with b&w/2D.