Bug 42655 SourceAttachmentBlock does not use dialog font for all widgets [dialogs] [build path]
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
private void attachmentDialogFieldChanged(DialogField field) {
		if (field == fFileNameField) {
			fNameStatus= updateFileNameStatus();
		} else if (field == fWorkspaceButton) {
			IPath jarFilePath= chooseInternalJarFile();
			if (jarFilePath != null) {
				fFileNameField.setText(jarFilePath.toString());
			}
			return;
		} else if (field == fExternalFolderButton) {
			IPath folderPath= chooseExtFolder();
			if (folderPath != null) {
				fFileNameField.setText(folderPath.toString());
			}
			return;
		}
		doStatusLineUpdate();
	}	
		
	private void doStatusLineUpdate() {
		fFileNameField.enableButton(canBrowseFileName());
		
		
		if (fFullPathResolvedLabel != null) {
			fFullPathResolvedLabel.setText(getResolvedLabelString(fFileNameField.getText(), true));
		}
		
		IStatus status= StatusUtil.getMostSevere(new IStatus[] { fNameStatus });
		fContext.statusChanged(status);