[issues] Make tag filter work in a more useful way

Author: LeaVerou

issues.html

@@ -66,7 +66,7 @@ <h2>
 			<legend>Filter by tag</legend>
 
 			<label property="tagFilter" mv-multiple mv-value="unique(issue.tag)">
-				<input type="checkbox" property="show" checked>
+				<input type="checkbox" property="show">
 				<span property="tagFilter"></span>
 				({count(issue.tag = tagFilter)})
 			</label>
@@ -75,7 +75,7 @@ <h2>
 	</div>
 
 	<article property="issue" mv-multiple class="status-{status} issue-{openness} {if(filtered, 'filtered')}" id="issue-{id}">
-		<meta property="filtered" content="{(status and !get(statusFilter, status).show) or !get(openFilter, openness).show or (count(tag) and count(selectedTags) and !intersects(tag, selectedTags))}" />
+		<meta property="filtered" content="{(status and !get(statusFilter, status).show) or !get(openFilter, openness).show or (count(selectedTags) and !intersects(tag, selectedTags))}" />
 
 		<h1>
 			<a href="#issue-{id}" property="id" mv-attribute="null" mv-default="{$previous.id + 1}">1</a>