As a Roblox developer, it is currently impossible to use a plugin to show a script editor pane without changing the users cursor position (if it is already open).
Currently Plugin:OpenScript( Instance script , int lineNumber ) defaults to 0 when no lineNumber is provided. I propose a small change where if an editor is already open for that script, then it defaults to wherever the current cursor location is.
This problem could also be solved by woot3’s suggestion here Plugin script cursor methods
This would allow plugins to provide more consistent behaviour within Roblox Studio.