cm_VisTwoDriveButtons doesn't change pushed button

[MVV]

1. Open different drives in a panels.
2. Then activate right panel.
3. Disable second drive bar via Configuration dialog. Notice that drive letter of the drive bar reflects right panel's drive.
4. Enable second drive bar.
5. Add buttonbar button with cm_VisTwoDriveButtons command and click it to disable second drive bar. Notice that the drive bar still shows left panel's drive. But it should switch to right panel's drive as in step 3.

[MVV]

Thanks, works fine in TC 8 final.

[Flint]

Confirm the bug in rc2 and fix in 8.0 final.