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
desc.setText(NewWizardMessages.getString("SourceAttachmentBlock.filename.description")); 
			desc.setLayoutData(gd);
			DialogField.createEmptySpace(composite, 1);
		}
		
		fFileNameField.doFillIntoGrid(composite, 4);
		LayoutUtil.setWidthHint(fFileNameField.getTextControl(null), widthHint);
		LayoutUtil.setHorizontalGrabbing(fFileNameField.getTextControl(null));
		
		if (!isVariableEntry()) {
			
			DialogField.createEmptySpace(composite, 3);	
			fInternalButtonField.doFillIntoGrid(composite, 1);
		} else {
			
			DialogField.createEmptySpace(composite, 1);	
			fFullPathResolvedLabel= new CLabel(composite, SWT.LEFT);
			fFullPathResolvedLabel.setText(getResolvedLabelString(fFileNameField.getText(), true));
			fFullPathResolvedLabel.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_FILL));
			DialogField.createEmptySpace(composite, 2);			
		}
		
		fFileNameField.postSetFocusOnDialogField(parent.getDisplay());
				
		WorkbenchHelp.setHelp(composite, IJavaHelpContextIds.SOURCE_ATTACHMENT_BLOCK);
		return composite;
	}
	
		
	private class SourceAttachmentAdapter implements IStringButtonAdapter, IDialogFieldListener {