Discontinuities are inserted pretty much every time a procedure is added because the FMC doesn’t know if you want to connect that procedure with the existing plan or add more waypoints. In order to clear a discontinuity, you can simply delete it, or you can click on the first waypoint after the discontinuity and then press the line select key next to the discontinuity and the FMC will move that waypoint up.
This becomes only slightly more challenging when a discontinuity is preceded by a (vect) vector leg. This happens when a procedure ends with a vector - which occurs often at the beginning of a departure procedure or at the end of an arrival procedure. In these cases, if you want to connect the waypoints and not fly the vector, you need to pick up the waypoint after the discontinuity, like described above, but instead of inserting it on the discontinuity, insert it on the (vect) leg.
Hope that helps - there are some good youtube videos showing people removing disco legs also.