Reproduce: Install VS2019 | install MouseImpx64 | open a project | in file mimpwnds.xml add <item wndclass="HwndWrapper[DefaultDomain" horscroll="false" lockedscrolldirection="false" lockedwheeldelta="true" /> | reload in Admin mode both MouseImp and VS2019 | right mouse click on the text in Text Area or on a file in Solution Explorer.
Actual: No context menu is shown.
Expected: Context menu is shown.

Workaround: Need to make the right mouse click a second time to see the context menu.

FYI: in a program that shows keys events, after the first RMС, I see a whole bunch of artificial RMC-up/down events