diff --git a/html/can.js b/html/can.js
index 1c69bf14..a7504f93 100644
--- a/html/can.js
+++ b/html/can.js
@@ -36,7 +36,8 @@ var f=1;
 for(var i=0;i<xn;i++){var n=ar[nx+i];var x=ar[vx+i];var xo=(x-x0)/(x1-x0);if(c['skey']&&(i<(xn-1))&&(i%m)==0){gbe(c,xo,0);gln(c,xo,-0.01);gst(c);gfz(c,xo,0,0,-hi*1.5,n,'#00a050','center')}if(c['slines']){gbe(c,xo,0);gln(c,xo,1);gst(c)}}
 var xhr=x1-(x1%3600);
 gss(c,'brown');
-for(var i=xhr;i>=x0;i-=(6*3600)){var n=dfmt(i);var xo=(i-x0)/(x1-x0);if(c['tkey']){gbe(c,xo,0);gln(c,xo,-0.02);gst(c);gfz(c,xo,0,0,-hi*1.5,n,'brown','center')}if(c['tlines']){gbe(c,xo,0);gln(c,xo,1);gst(c)}}
+var tpos=2.7;if(c['over']){tpos=1.5}
+for(var i=xhr;i>=x0;i-=(6*3600)){var n=dfmt(i);var xo=(i-x0)/(x1-x0);if(c['tkey']){gbe(c,xo,0);gln(c,xo,-0.02);gst(c);gfz(c,xo,0,0,-hi*tpos,n,'brown','center')}if(c['tlines']){gbe(c,xo,0);gln(c,xo,1);gst(c)}}
 glw(c,0.1);
 gss(c,'black');
 if(c['smooth']){var xa=0,ya=0,xb=0,yb=0;
@@ -49,7 +50,7 @@ gbe(c,0,y);gln(c,1,y);gst(c);
 var t=''+av.toFixed(2);gfz(c,1,y,1,0,t,'red','left')
 }
 function sn(i,shi){if(shi.indexOf(' Shift ')<0){return ''+(i%10)}else{return shi.replace(/.* ([a-z])[a-z]*$/,'$1')}}
-function gc(c){var div=document.getElementById('can0');while(div.firstChild){div.removeChild(div.firstChild)}c['can']=document.createElement('canvas');c['can'].id='can';c['wx']=window.innerWidth;c['wy']=window.innerHeight;c['xm']=Math.round(c['wx']*0.9+0.5);c['ym']=Math.round(c['wy']*0.8+0.5);if(c['ym']>c['xm']){c['ym']=c['xm']}c['xo']=0.0;c['yo']=0.0;c['ctx']=c['can'].getContext('2d');c['ctx'].canvas.width=c['xm']+1;c['ctx'].canvas.height=c['ym']+1;div.appendChild(c['can']);div=document.getElementById('smooth');c['smooth']=(div&&div.checked);div=document.getElementById('skey');c['skey']=(div&&div.checked);div=document.getElementById('slines');c['slines']=(div&&div.checked);div=document.getElementById('tkey');c['tkey']=(div&&div.checked);div=document.getElementById('tlines');c['tlines']=(div&&div.checked);div=document.getElementById('zerob');c['zerob']=(div&&div.checked)}
+function gc(c){var div=document.getElementById('can0');while(div.firstChild){div.removeChild(div.firstChild)}c['can']=document.createElement('canvas');c['can'].id='can';c['wx']=window.innerWidth;c['wy']=window.innerHeight;c['xm']=Math.round(c['wx']*0.9+0.5);c['ym']=Math.round(c['wy']*0.8+0.5);if(c['ym']>c['xm']){c['ym']=c['xm']}c['xo']=0.0;c['yo']=0.0;c['ctx']=c['can'].getContext('2d');c['ctx'].canvas.width=c['xm']+1;c['ctx'].canvas.height=c['ym']+1;div.appendChild(c['can']);div=document.getElementById('smooth');c['smooth']=(div&&div.checked);div=document.getElementById('over');c['over']=(div&&div.checked);div=document.getElementById('skey');c['skey']=(div&&div.checked);div=document.getElementById('slines');c['slines']=(div&&div.checked);div=document.getElementById('tkey');c['tkey']=(div&&div.checked);div=document.getElementById('tlines');c['tlines']=(div&&div.checked);div=document.getElementById('zerob');c['zerob']=(div&&div.checked)}
 function gdrw(d){var c={};gc(c);
 gfs(c,'white');gss(c,'#0000c0');glw(c,0.5);gbd(c);
 var rows=d['rows'],ymin=-1,ymax=0,xmin=-1,xmax=0;
diff --git a/pool/page_usperf.php b/pool/page_usperf.php
index 4c8aeed3..650df30f 100644
--- a/pool/page_usperf.php
+++ b/pool/page_usperf.php
@@ -20,6 +20,7 @@ function dousperf($data, $user)
 	$pg .= ">shift lines&nbsp;";
 	$pg .= "&nbsp;<input type=checkbox id=tkey onclick='godrw()'>time key&nbsp;";
 	$pg .= "&nbsp;<input type=checkbox id=tlines onclick='godrw()'>time lines&nbsp;";
+	$pg .= "&nbsp;<input type=checkbox id=over onclick='godrw()'>key overlap&nbsp;";
 	$pg .= "&nbsp;<input type=checkbox id=smooth onclick='godrw()'>smooth&nbsp;";
 	$pg .= "&nbsp;<input type=checkbox id=zerob onclick='godrw()'>zero based</div>";
 	$pg .= "<div id=can0><canvas id=can width=1 height=1>";