Program: 79301
Project: 79301
Buggy source:
public void widgetSelected(SelectionEvent e){
  Object oSource=e.getSource();
  if (oSource.equals(btnDown)) {
    fireHandleEvent(MOUSE_CLICKED_EVENT);
    toggleDropDown();
  }
 else   if (oSource.equals(this.btnImage)) {
    FileDialog fDlg=new FileDialog(this.getShell(),SWT.OPEN);
    cmpDropDown.getParent().dispose();
    fDlg.setFilterExtensions(saImageTypes);
    String sStartFolder=System.getProperty("String_Node_Str");
    String sImageFile="String_Node_Str";
    if (fCurrent instanceof Image) {
      String sFullPath=((Image)fCurrent).getURL().toString();
      sImageFile=sFullPath.substring(sFullPath.lastIndexOf("String_Node_Str") + 1);
      sStartFolder=sFullPath.substring(0,sFullPath.lastIndexOf("String_Node_Str"));
    }
    fDlg.setFilterPath(sStartFolder);
    fDlg.setFileName(sImageFile);
    String sImgPath=fDlg.open();
    if (sImgPath == null) {
      return;
    }
    try {
      new URL(sImgPath);
    }
 catch (    MalformedURLException e1) {
      sImgPath="String_Node_Str" + fDlg.getFilterPath() + File.separator+ fDlg.getFileName();
    }
    if (sImgPath != null && sImgPath.trim().length() > 0) {
      Image imgFill=AttributeFactory.eINSTANCE.createImage();
      imgFill.setURL(sImgPath);
      this.setFill(imgFill);
      fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
    }
  }
 else   if (oSource.equals(this.btnCustom)) {
    ColorDialog cDlg=new ColorDialog(this.getShell(),SWT.NONE);
    cmpDropDown.getParent().dispose();
    if (fCurrent instanceof ColorDefinition) {
      cDlg.setRGB(new RGB(((ColorDefinition)this.fCurrent).getRed(),((ColorDefinition)this.fCurrent).getGreen(),((ColorDefinition)this.fCurrent).getBlue()));
    }
    cDlg.open();
    RGB rgb=cDlg.getRGB();
    if (rgb != null) {
      ColorDefinition cdNew=AttributeFactory.eINSTANCE.createColorDefinition();
      cdNew.set(rgb.red,rgb.green,rgb.blue);
      this.setFill(cdNew);
      fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
    }
  }
 else   if (oSource.equals(this.btnGradient)) {
    GradientEditorDialog ged=null;
    cmpDropDown.getParent().dispose();
    if (fCurrent instanceof Gradient) {
      ged=new GradientEditorDialog(this.getShell(),(Gradient)fCurrent);
    }
 else {
      ged=new GradientEditorDialog(this.getShell(),null);
    }
    if (ged.getGradient() != null) {
      Fill fTmp=ged.getGradient();
      if (fCurrent == null || !(fCurrent.equals(fTmp))) {
        this.setFill(fTmp);
        fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
      }
    }
  }
 else   if (oSource.equals(btnTransparent)) {
    if (btnTransparent.getSelection()) {
      fCurrent=null;
    }
 else {
      fCurrent=ColorDefinitionImpl.WHITE();
    }
    this.setFill(fCurrent);
    fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
    cmpDropDown.getParent().dispose();
  }
}

Fixed version (ground truth):
public void widgetSelected(SelectionEvent e){
  Object oSource=e.getSource();
  if (oSource.equals(btnDown)) {
    fireHandleEvent(MOUSE_CLICKED_EVENT);
    toggleDropDown();
  }
 else   if (oSource.equals(this.btnImage)) {
    FileDialog fDlg=new FileDialog(this.getShell(),SWT.OPEN);
    cmpDropDown.getParent().dispose();
    fDlg.setFilterExtensions(saImageTypes);
    String sStartFolder=System.getProperty("String_Node_Str");
    String sImageFile="String_Node_Str";
    if (fCurrent instanceof Image) {
      String sFullPath=((Image)fCurrent).getURL().toString();
      sImageFile=sFullPath.substring(sFullPath.lastIndexOf("String_Node_Str") + 1);
      sStartFolder=sFullPath.substring(0,sFullPath.lastIndexOf("String_Node_Str"));
    }
    fDlg.setFilterPath(sStartFolder);
    fDlg.setFileName(sImageFile);
    String sImgPath=fDlg.open();
    if (sImgPath == null) {
      return;
    }
    try {
      new URL(sImgPath);
    }
 catch (    MalformedURLException e1) {
      sImgPath="String_Node_Str" + fDlg.getFilterPath() + File.separator+ fDlg.getFileName();
    }
    if (sImgPath != null && sImgPath.trim().length() > 0) {
      Image imgFill=AttributeFactory.eINSTANCE.createImage();
      imgFill.setURL(sImgPath);
      this.setFill(imgFill);
      fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
    }
  }
 else   if (oSource.equals(this.btnCustom)) {
    ColorDialog cDlg=new ColorDialog(this.getShell(),SWT.NONE);
    cmpDropDown.getParent().dispose();
    int iTrans=0;
    if (fCurrent instanceof ColorDefinition) {
      iTransparency=((ColorDefinition)fCurrent).getTransparency();
      cDlg.setRGB(new RGB(((ColorDefinition)this.fCurrent).getRed(),((ColorDefinition)this.fCurrent).getGreen(),((ColorDefinition)this.fCurrent).getBlue()));
    }
    cDlg.open();
    RGB rgb=cDlg.getRGB();
    if (rgb != null) {
      ColorDefinition cdNew=AttributeFactory.eINSTANCE.createColorDefinition();
      cdNew.set(rgb.red,rgb.green,rgb.blue);
      cdNew.setTransparency((bTransparencyChanged) ? this.iTransparency : iTrans);
      this.setFill(cdNew);
      fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
    }
  }
 else   if (oSource.equals(this.btnGradient)) {
    GradientEditorDialog ged=null;
    cmpDropDown.getParent().dispose();
    if (fCurrent instanceof Gradient) {
      ged=new GradientEditorDialog(this.getShell(),(Gradient)fCurrent);
    }
 else {
      ged=new GradientEditorDialog(this.getShell(),null);
    }
    if (ged.getGradient() != null) {
      Fill fTmp=ged.getGradient();
      if (fCurrent == null || !(fCurrent.equals(fTmp))) {
        this.setFill(fTmp);
        fireHandleEvent(FillChooserComposite.FILL_CHANGED_EVENT);
      }
    }
  }
 else   if (oSource.equals(srTransparency)) {
    iTransparency=srTransparency.getSelection();
    lblCurrentTransparency.setText(String.valueOf(iTransparency));
    bTransparencyChanged=true;
  }
}