Turn off grayscale icons when the window is minimized in plasma 5:
/usr/share/plasma/plasmoids/org.kde.plasma.taskmanager/contents/ui/Task.qml
PlasmaCore.IconItem {
id: icon
anchors.fill: parent
visible: false
active: task.containsMouse
enabled: true // Original: !(model.Minimized && !plasmoid.configuration.showOnlyMinimized)
source: model.DecorationRole
onVisibleChanged: {
if (visible && busyIndicator) {
busyIndicator.destroy();
}
}
}