What did the court decide in McKaskle v. Wiggins?
Answered for: US
Thus, Faretta rights are adequately vindicated in proceedings outside the presence of the jury if the pro se defendant is allowed to address the court freely on his own behalf and if disagreements between counsel and the pro se defendant are resolved in the defendant's favor whenever the matter is one that would normally be left to the discretion of counsel.
The Court addressed how far standby counsel may participate without infringing a self-represented defendant's Faretta rights. The sentence above is the court in its own words.
This answer is true in US and nowhere else on this site. Another jurisdiction is another answer, or an honest gap: see what has been read for US.