when attaching to new buffer, no cursor information is shown

[alemidev]

example:
workspace "abc"

• buffer "A"
• buffer "B"

user #1 and #2 both in workspace

user #1 attached to A, selects whole buffer
user #2 is not attached to A
user #2 now attaches to A and sees no selection

---

this could be solved storing cursor data for buffers we don't manage yet, and upon attaching drawing cursor data that we pre-stored