I use a couple of 3-button buttons with the LMB invoking Opus built-in Sync and the RMB invoking Beyond Compare. The first button operates on the current top level folder which can, of course, be the root folder of a drive - e.g. C:. The second button operates on a selected folder.
LMB1 code:
@nodeselect
Go "{sourcepath$}" DUALPATH "{dlgstring|Type a drive letter..|E}:\{sourcepath$|noroot}" LAYOUT=SyncLock
RMB1 code:
@nodeselect
@nofilenamequoting
@set dir={alias|homeroot}\utilities\BC3\
@set app=Bcompare.exe
cd {$dir}
{$dir}{$app} "{sourcepath$}" "{dlgstring|Type a drive letter..|E}:\{sourcepath$|noroot}"
LMB2 code:
@dirsonly
@nodeselect
Go "{filepath$}" DUALPATH "{dlgstring|Type a drive letter..|E}:\{filepath$|noroot}" LAYOUT=SyncLock
RMB2 code: @dirsonly @nodeselect @nofilenamequoting @set dir={alias|homeroot}\utilities\BC3 @set app=Bcompare.exe
cd {$dir}
{$dir}{$app} "{filepath$}" "{dlgstring|Type a drive letter..|E}:{filepath$|noroot}"[/code]
I use Beyond Compare portable. You will need to change the @set dir= definitions above to point to where your Bcompare.exe is located.
For the internal commands, I use a saved layout called "SyncLock" to activate the synchronise utility panel and force navigation lock on.
My default target drive is E: simply because that is where I keep my local backups. The commands allow overriding the default.