Hi Markus,
instead of using the options on the layout, you also can pass options for histograms from within the QC tasks themselves. For the TPC, Thomas has written a small helper class, which you can find here:
O2/Detectors/TPC/qc/include/TPCQC/Helpers.h
O2/Detectors/TPC/qc/src/Helpers.cxx
This comes with several helpful little functions, the ones interesting for you are:
void helpers::setStyleHistogram2D(TH2& histo)
void helpers::setStyleHistogram2D(std::vector<TH2F>& histos)
First one sets some options for one 2D histogram, 2nd one calls the first for all 2D hists when giving them in a vector.
In the QC part, you just have to call this, e.g. look at
QualityControl/Modules/TPC/src/PID.cxx
In the function void PID::initialize the helper is called and you get rid of the stat box:
o2::tpc::qc::helpers::setStyleHistogram2D(mQCPID.getHistograms2D());
Especially in cases, where you for sure do not want to have the stat box, this is a nice solution as you do not have to care, no matter in which layout the plot is used.
Cheers,
Stefan