This code looks really repetitive. Any way to shorten it?
one way of shortening might be: 


having a HashMap consisting of pairs of objects (sender) and Tools. This way you could look up the appropriate Tool for each sender in one single method like this:

HashMap&lt;object, Tool&gt; hashMap = new HashMap&lt;object, Tool&gt;( );

hashMap.put(sender1, new Brush(tileLayers));

// ...add the rest of the Tools
private void clickHandler(object sender, EventArgs e)
{
    currentTool = hashMap.get(sender);

    UncheckToolstripButtons( );
    tspBrush.Checked = true;
}

If tspXxxx cannot be retrieved from the sender directly, use another HashMap to map senders to tspXxxx objects.