Bug 29755 Attach source does not allow one to select a folder... [build path]
When opening some .class that does not yet have a source attachment eclipse shows a text version of the interface defintion and a button for Attaching source. When pressing this button a window appaer where one can enter the name/location of a folder, zip or jar for the source. There are also a button for choosing it via a file selection dialog and this works fine for zip and jar files - but not for selecting a directory :( Workaround is just to enter the directory manually.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
SourceAttachmentAdapter adapter= new SourceAttachmentAdapter();
		
		
		if (isVariableEntry()) {
			fFileNameField= new VariablePathDialogField(adapter);
			fFileNameField.setDialogFieldListener(adapter);
			fFileNameField.setLabelText(NewWizardMessages.getString("SourceAttachmentBlock.filename.varlabel")); 
			fFileNameField.setButtonLabel(NewWizardMessages.getString("SourceAttachmentBlock.filename.external.varbutton")); 
			((VariablePathDialogField)fFileNameField).setVariableButtonLabel(NewWizardMessages.getString("SourceAttachmentBlock.filename.variable.button")); 
					
		} else {
			fFileNameField= new StringButtonDialogField(adapter);
			fFileNameField.setDialogFieldListener(adapter);
			fFileNameField.setLabelText(NewWizardMessages.getString("SourceAttachmentBlock.filename.label")); 
			fFileNameField.setButtonLabel(NewWizardMessages.getString("SourceAttachmentBlock.filename.external.button")); 
		
			fInternalButtonField= new SelectionButtonDialogField(SWT.PUSH);
			fInternalButtonField.setDialogFieldListener(adapter);
			fInternalButtonField.setLabelText(NewWizardMessages.getString("SourceAttachmentBlock.filename.internal.button")); 
			
		}	
	
		
		setDefaults();
	}
	
	public void setDefaults() {
		if (fEntry.getSourceAttachmentPath() != null) {
			fFileNameField.setText(fEntry.getSourceAttachmentPath().toString());