This plugin is out of date. It is using a deprecated function for the home URL, PHP shorttags (which don’t work in later versions of PHP), odd defaults, and a margin on the QR code. It also puts a link below the QR code to the author’s site.
There is no error feedback on bad color numbers either.
(And the QR code image is embedded in the page, so it is not cached.)
When using the Responsive Theme by ThemeID, putting your QrCodeAdv in the a Footer Widget area, breaks all the remaining Footer Widget areas.
From what I can tell, the way your plugin implements the DIV tags, is over-riding the DIV tags for the footer widgets, built into the theme.
Before installing your plugin, the footer widget code is identified as:
<div class="grid col-220">
<div class="grid col-220">
<div class="grid col-220">
<div class="grid col-220 fit">After installing your plugin, the footer widget code is identified as:
<div id="colorwp_qr_widget-3" class="widget-wrapper colorwp_qr_widget">
<div class="grid col-220">
<div class="grid col-220">
<div class="grid col-220 fit">…completely removing the containing DIV.
FYI: it looks to have the same issue in verticle widgets as well, but because they are verticle, it doesn’t have the same negative effect.
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