Make SelectionBar end/length radio buttons behave normally

They had lost the focus/voice-over functionality because I added code to draw them in the
theme colour.  Now I disable that code, IF recolouring is both set and active.  This will happen
for example, if Hi-Contrast is used with the Hi-Contrast system theme.

src/Theme.cpp

@@ -282,6 +282,7 @@ void Theme::RegisterColours()
 ThemeBase::ThemeBase(void)
 {
    bRecolourOnLoad = false;
+   bRecolouringIsActive = false;
 }
 
 ThemeBase::~ThemeBase(void)
@@ -321,6 +322,7 @@ void ThemeBase::LoadTheme( teThemeType Theme )
       CreateImageCache();
 #endif
    }
+   bRecolouringIsActive = false;
    if( bRecolourOnLoad )
       RecolourTheme();
    bRecolourOnLoad = false;
@@ -356,9 +358,10 @@ void ThemeBase::RecolourTheme()
       + abs( From.Green() - To.Green() )
       + abs( From.Blue() - To.Blue() );
 
-   // Don't recolour if difference is too big, or no difference.
+   // Don't recolour if difference is too big.
    if( d  > 120 )
       return;
+   bRecolouringIsActive = true;
 
    // A minor tint difference from standard does not need 
    // to be recouloured either.  Includes case of d==0 which is nothing

src/Theme.h

@@ -117,6 +117,7 @@ public:
    void WriteImageDefs( );
    void WriteImageMap( );
    static bool LoadPreferredTheme();
+   bool RecolouringIsActive(){ return bRecolouringIsActive;};
    void RecolourBitmap( int iIndex, wxColour From, wxColour To );
    void RecolourTheme();
 
@@ -127,7 +128,8 @@ public:
    wxCursor & Cursor( int iIndex );
    wxFont   & Font( int iIndex );
    wxSize ImageSize( int iIndex );
-   bool bRecolourOnLoad;
+   bool bRecolourOnLoad;  // Request to recolour.
+   bool bRecolouringIsActive;  // We're actually doing it.
 
    void ReplaceImage( int iIndex, wxImage * pImage );
 

src/toolbars/SelectionBar.cpp

@@ -164,13 +164,18 @@ void SelectionBar::Populate()
    gPrefs->Read(wxT("/ShowSelectionLength"), &showSelectionLength);
 
    {
+      bool bCustomRadioLabels = !theTheme.RecolouringIsActive();
       // Can't set textcolour of radio buttons.
       // so instead we make the text empty and add in two wxStaticTexts
       // and we can set the colour of those.
-      // Slight regression relative ot Audacity in that this text is not 
+      // Slight regression relative ot Audacity, in that this text is not 
       // clickable/active.  You have to click on the actual button.
+      // And can't tab between and hear the labels with voice over.
+      // So VI users should use blend themes (which is the default).
+      // Should not be a hardship for them, as themes make little difference 
+      // for them, except Hi-Contrast, which should be used with recolouring.
       auto hSizer = std::make_unique<wxBoxSizer>(wxHORIZONTAL);
-      mRightEndButton = safenew wxRadioButton(this, OnEndRadioID, wxT(""),
+      mRightEndButton = safenew wxRadioButton(this, OnEndRadioID, bCustomRadioLabels ? wxT("") : _("End"),
          wxDefaultPosition, wxDefaultSize,
          wxRB_GROUP);
       mRightEndButton->SetName(_("End"));
@@ -178,21 +183,27 @@ void SelectionBar::Populate()
       mRightEndButton->SetValue(!showSelectionLength);
       hSizer->Add(mRightEndButton,
          0, wxRIGHT | wxALIGN_CENTER_VERTICAL, 5);
+      if( bCustomRadioLabels )
+      {
          wxStaticText * pEndText = safenew wxStaticText(this, -1, _("End"));
          pEndText->SetForegroundColour( clrText );
          hSizer->Add(pEndText,
             0, wxRIGHT | wxALIGN_CENTER_VERTICAL, 5);
+      }
 
-      mRightLengthButton = safenew wxRadioButton(this, OnLengthRadioID, wxT(""));
+      mRightLengthButton = safenew wxRadioButton(this, OnLengthRadioID, bCustomRadioLabels ? wxT(""): _("Length"));
       mRightLengthButton->SetName(_("Length"));
       mRightLengthButton->SetForegroundColour( clrText );
       mRightLengthButton->SetValue(showSelectionLength);
       hSizer->Add(mRightLengthButton,
          0, wxALIGN_CENTER_VERTICAL | wxRIGHT, 5);
+      if( bCustomRadioLabels )
+      {
          wxStaticText * pLengthText = safenew wxStaticText(this, -1, _("Length"));
          pLengthText->SetForegroundColour( clrText );
          hSizer->Add(pLengthText,
             0, wxRIGHT | wxALIGN_CENTER_VERTICAL, 5);
+      }
 
 #if defined(__WXMSW__)
       // Refer to Microsoft KB article 261192 for an explanation as