I can't understand why this is becoming such a big deal. There are many other soultions to this simple (and i do mean SIMPLE) problem of a placing a hemispherical cap on the end of a tube. Here are three solutions which don't require a save and reload :

1. draw a sphere, rotate it so the edge is tucked into cylinder. Select both items and boolean union. DONE.
2. draw an 90 degree arc at the end of an open tube, then revolve it. Select the tube and the revolve and join them. DONE.
3. draw a 180 arc at the end of the open "tube" surface. Select that arc and split it at the midpoint, leaving two 90 degree arcs. Select the tube's edge, and create a new surface by using the Sweep command, using the 2 arcs as rails. Select the swept surface and join to the tube surface. DONE.

jonah