Update paramenter range when performing a contour scan

Dear all.
I’m currently having problems with the following task. I am trying to perform an NLL fit with parameters allowed in a wide range and then, after having minimized the likelihood and saved the result to run a contour in a RESTRICTED range…
so to say

m1 = new RooMinuit(*L);
m1->minos() ;
m1->migrad() ;
//HERE I want to update the range of par1
RooPlot *frame2 = m1->contour(*par1,*par2,1,2);
Unfortunately I see that the contour, regardless what I set just before the call to the tool, uses the -10 10 range of par1, resulting in a lot of error messages (since the -10,0 range covers a part of the space that is actually unphysical giving a negative likelihood) and an abnormous fit running time…

Is there ANY way to obtain a contour plot in a range different from the one used to minimize the likelihood?