tx_wsscss.variables in MultiDomain Environment

[bh-teufels]

in a multidomain installation i have different primary color for each site.
i set the colors as follows:

[1 in tree.rootLineIds]
plugin.tx_wsscss.variables {
primary = #FF0000
}
[END]

[10 in tree.rootLineIds]
plugin.tx_wsscss.variables {
primary = #00FF00
}
[END]

But if i changed between the pages the Color changes once but ist then cached? and stay the same.