This is just a preliminary report. JS ONLY
I've found that on first load, displaying a plugin it may not have its width and height set without explicit width and height attributes. They would be 0.
plugins declared out of scene
url is then changed in scene
Only happens once, loading, loaded all good. Looks like some sort of timing issue. Perhaps if url is changed when plugin is loading.. width and height won't be set correctly for new url. Yes that a good theory!
PHP
<plugin name="contactus" align="center" x="0" y="0" zorder="5" edge="center" keep="true" url="%SWFPATH%/skin/textwindow_<?php print $style ?>.png" onhover="showtext(Close contact us, buttonstyle);" onclick="hidewindows()" alpha="0" autoalpha="true" visible="false" />
<plugin name="share" align="center" x="0" y="0" zorder="5" edge="center" keep="true" url="%SWFPATH%/skin/textwindow_<?php print $style ?>.png" onhover="showtext(Close share, buttonstyle);" onclick="hidewindows()" alpha="0" autoalpha="true" visible="false" />
<plugin name="contactus_closebutton" parent="contactus" url="%SWFPATH%/skin/close60.png" x="13" y="10" width="40" height="40" align="righttop" edge="center" zorder="12" onloaded="if (ishtml5, set(x,15);set(y,12);set(width,60);set(height,60););" onclick="hidewindows()" onover="set(alpha,1)" onout="set(alpha,0.7)" ondown="set(alpha,1)" onup="set(alpha,0.7)" alpha="0.7" keep="true" />
<plugin name="share_closebutton" parent="share" url="%SWFPATH%/skin/close60.png" x="13" y="10" width="40" height="40" align="righttop" edge="center" zorder="12" onloaded="if (ishtml5, set(x,15);set(y,12);set(width,60);set(height,60););" onclick="hidewindows()" onover="set(alpha,1)" onout="set(alpha,0.7)" ondown="set(alpha,1)" onup="set(alpha,0.7)" alpha="0.7" keep="true" />