Open Calc and right click on first sheet on sheet panel in the bottom. In 5.1 pops up small menu, consisting of 3 entries: Copy, Paste and Cut. Please fix it and bring normal menu back
Testing it on Libreoffice 5.1.0.1 on Linux I see the normal menu with 11 entries. Could you please test it on more recent version?
Downloaded latest set of packages from site - bug is fixed!