Extending the plateau luminosity-duration anticorrelation

X-ray light curves of Swift Gamma-ray Bursts (GRBs) often show a plateau phase between the initial steep decay and the standard afterglow decay. The plateau luminosity and the rest frame plateau end time are known to be anticorrelated. Our aim is to test whether GRBs that show no evidence of plateau can be considered as "very short plateau" cases matching the above correlation. We analyze a sample of 50 GRBs observed by Swift with known redshifts (z), estimating the end time of the plateau and the 0.3-10 keV luminosity at that time. We then consider the GRBs with known z and no evidence of plateau. We confirm the existence of the correlation and provide a unified picture showing that also those X-ray light curves with no evidence of plateau are consistent with it assuming that the start epoch of the long duration afterglow decay is a plateau duration upper limit. We suggest that this result may represent a clue for a unified interpretation of the anticorrelation in the framework of multicomponent models of X-ray emission from GRBs.