I'm making a custom stylesheet to add to doxygen output files which is aimed at making website elements not selectable, so that only the useful code/text is selectable. Below is an example of a CSS rule to remove line numbers. Although it seems to select the correct classes, using select-all or dragging with a mouse and then copy/pasting into a text editor still copies over the line numbers. Why does this happen? Furthermore, how do I prevent it?
<div class="fragment"><div class="line"><a name="l00099"></a><span class="lineno"> 99</span> {</div>
<div class="line"><a name="l00100"></a><span class="lineno"> 100</span>  <a class="code" href="class_talon.html#a139bb330021efa545fd6047fa291dbeb">Set</a>(output);</div>
<div class="line"><a name="l00101"></a><span class="lineno"> 101</span> }</div>
<div class="ttc" id="class_talon_html_a139bb330021efa545fd6047fa291dbeb"><div class="ttname"><a href="class_talon.html#a139bb330021efa545fd6047fa291dbeb">Talon::Set</a></div><div class="ttdeci">virtual void Set(float value, uint8_t syncGroup=0)</div><div class="ttdef"><b>Definition:</b> <a href="_talon_8cpp_source.html#l00070">Talon.cpp:70</a></div></div>
</div>
<style>
.lineno {
background-color: red !important;
-webkit-touch-callout: none;
-webkit-user-select: none;
-khtml-user-select: none;
-moz-user-select: none;
-ms-user-select: none;
user-select: none;
}
.line:not(.lineno) {
background-color: blue;
-webkit-touch-callout: text !important;
-webkit-user-select: text !important;
-khtml-user-select: text !important;
-moz-user-select: text !important;
-ms-user-select: text !important;
user-select: text !important;
}
</style>