Ok, so after posting I realised that my drawing had many points which weren't properly connected.. they had gaps. I zoomed in a lot to
see them. This brings me to my next question which is when I try to click on for example the centre of a circle , several little crosses show up
so I don't know which one to click on:









Similarly, the same thing happens for a line too where there appear to be several little crosses and it's confusing which one to click on. This is particularly
problematic when I'm drawing one quadrant which needs to be mirrored to make a full circular pattern.

Could someone please clarify?

Many thanks!
Gunter