Fix defaults for unchosen optional values.

Previously when using a scriptable via dialog the unchosen optional values from the dialog were still being used.
Now unchosen options are reset to their default values, if they would be used.

src/commands/DragCommand.cpp

@@ -81,6 +81,16 @@ void DragCommand::PopulateOrExchange(ShuttleGui & S)
 
 bool DragCommand::Apply(const CommandContext & context)
 {
+   // Defaults if no value...
+   if( !bHasFromX )
+      mFromX = 200.0;
+   if( !bHasFromY )
+      mFromY = 10;
+   if( !bHasToX )
+      mToX = 400;
+   if( !bHasToY )
+      mToY = 10;
+
    wxWindow * pWin = context.GetProject();
    wxWindow * pWin1 = nullptr;
    wxMouseEvent Evt( wxEVT_MOTION );

src/commands/SelectCommand.cpp

@@ -88,6 +88,14 @@ bool SelectTimeCommand::Apply(const CommandContext & context){
    if( !bHasT0 && !bHasT1 )
       return true;
 
+   // Defaults if no value...
+   if( !bHasT0 )
+      mT0 = 0.0;
+   if( !bHasT1 )
+      mT1 = 0.0;
+   if( !bHasRelativeSpec )
+      mRelativeTo = 0;
+
    AudacityProject * p = context.GetProject();
    double end = p->GetTracks()->GetEndTime();
    double t0;
@@ -148,6 +156,12 @@ bool SelectFrequenciesCommand::Apply(const CommandContext & context){
    if( !bHasBottom && !bHasTop )
       return true;
 
+   // Defaults if no value...
+   if( !bHasTop )
+      mTop = 0.0;
+   if( !bHasBottom )
+      mBottom = 0.0;
+
    context.GetProject()->SSBL_ModifySpectralSelection(
       mBottom, mTop, false);// false for not done.
    return true;
@@ -195,6 +209,13 @@ bool SelectTracksCommand::Apply(const CommandContext &context)
 {
    int index = 0;
    TrackList *tracks = context.GetProject()->GetTracks();
+
+   // Defaults if no value...
+   if( !bHasNumTracks ) 
+      mNumTracks = 1.0;
+   if( !bHasFirstTrack ) 
+      mFirstTrack = 0.0;
+
    // Stereo second tracks count as 0.5 of a track.
    double last = mFirstTrack+mNumTracks;
    double first = mFirstTrack;

src/commands/SetClipCommand.cpp

@@ -77,6 +77,8 @@ bool SetClipCommand::ApplyInner( const CommandContext & context, Track * t )
    if( t->GetKind() != Track::Wave) 
       return true;
    
+   // if no 'At' is specified, then any clip in any selected track will be set.
+
    WaveTrack *waveTrack = static_cast<WaveTrack*>(t);
    wxASSERT( waveTrack );
    WaveClipPointers ptrs( waveTrack->SortedClipArray());

src/commands/SetEnvelopeCommand.cpp

@@ -56,6 +56,10 @@ bool SetEnvelopeCommand::ApplyInner( const CommandContext & context, Track * t )
    if( (t->GetKind() != Track::Wave)) 
       return true;
 
+   // if no time is specified, then 
+   //   - delete deletes any envelope in selected tracks.
+   //   - value is not set for any clip
+
    WaveTrack *waveTrack = static_cast<WaveTrack*>(t);
    WaveClipPointers ptrs( waveTrack->SortedClipArray());
    for(auto it = ptrs.begin(); (it != ptrs.end()); it++ ){

src/commands/SetTrackInfoCommand.cpp

@@ -109,7 +109,7 @@ bool SetTrackBase::Apply(const CommandContext & context  )
 
 bool SetTrackStatusCommand::DefineParams( ShuttleParams & S ){ 
    SetTrackBase::DefineParams( S );
-   S.OptionalN( bHasTrackName      ).Define(     mTrackName,      wxT("Name"),       wxT("Unnamed") );
+   S.OptionalN( bHasTrackName      ).Define(     mTrackName,      wxT("Name"),       _("Unnamed") );
    // There is also a select command.  This is an alternative.
    S.OptionalN( bHasSelected       ).Define(     bSelected,       wxT("Selected"),   false );
    S.OptionalN( bHasFocused        ).Define(     bFocused,        wxT("Focused"),    false );