What are the grounds for error in denying a motion to withdraw a guilty plea?

As we have noted, appellate counsel has filed a brief pursuant to Wende and asks this court to review the record for possible error. To assist the court in its review of the record, and in compliance with Anders v. California (1967) 386 U.S. 738 (Anders), counsel has identified the following possible, but not arguable issues for our consideration:

1. Whether the court erred in not allowing Stephens to see part of the discovery;

2. Whether the court erred in denying the motion to strike the "strike" prior;

3. Whether the court erred in declining to strike the serious felony prior;

4. Whether the court erred in allowing Stephens to represent himself;

5. Whether the court erred in denying the motion to withdraw the guilty plea; and