How do we apply / utilize themes in Apex DC++ 1.2.22 ? 
 
I found out: 
 
You NEED to create the </themes> folder, optimally in installation folder of ApexDC++ 
Copy theme files that you've downloaded or borrowed int this "Themes" folder you've created.  
In the client, open settings>appearance>Colors & Fonts click the Import Theme botton. 
 
In the window that you need to browse for theme files you need to select "All Files" in the <File types> pull down menu to display 
the theme files you have downloaded or borrowed and placed in the themes folder you have created . 
 
Theme files have .xml extensions which are not immediately visible in the window that opens when you click 
the "Import theme " button in the settings>appearance>Colors & Fonts tab