In Toad 10.5, CodeXpert cannot be found under Editor Desktop Panels via Editor menu or right-click menu.
Per Toad 10.5 Release Notes due to future improvements of CodeXpert and Editor windows, the CodeXpert window can only be accessed using "Send to CodeXpert" icon from Editor toolbar or via Database | Diagnose menu option:
CodeXpert is undergoing improvements that will continue to develop in future releases of Toad. One of the changes for this release includes a new workflow for sending scripts from CodeXpert to the Editor, which improves the Editor's performance and is also a preparation for future CodeXpert improvements.
To use CodeXpert and the Editor together:
1) Open the code in the Editor.
2) Click (Send to CodeXpert) in the Editor toolbar.
3) Click (Perform a code quality review).
4) Click (Send results to Editor) in the results toolbar.
Note: If "Send to CodeXpert" icon cannot be located under Editor Toolbar, then right-click anywhere on the toolbar and select Restore Defaults option.