I found a small bug in the TagCloud.php code in line 201:

Here is the mistake:
The "clear" tags link checks the wrong variable and inserts an ampersand instead of a ? to the URL, making it invalid.


This is the line: it checks for $strUrl instead of the correct $strEmptyUrl, as that is the URL to be used for the link.

if (strpos($strEmptyUrl, '?') !== false)


Code:
		if ($this->tag_show_reset)
		{
			$strEmptyUrl = ampersand($this->generateFrontendUrl($pageArr, ''));
			if (strlen($strParams))
			{
				if (strpos($strEmptyUrl, '?') !== false)
				{
					$strEmptyUrl .= '&' . $strParams;
				}
				else
				{
					$strEmptyUrl .= '?' . $strParams;
				}
			}
			$this->Template->empty_url = $strEmptyUrl;
			$this->Template->lngEmpty = $GLOBALS['TL_LANG']['tl_module']['tag_clear_tags'];
		}