Updated the documentation

Author: sadko4u

src/doc/manuals/controls.php

@@ -409,7 +409,12 @@
 <p>For all knobs (especially when they are stiff) quick adjustment of parameter may be achived by left-clicking
 knob's scale. Also, additionally mouse button may be hold and parameter will be adjusted by moving mouse
 clockwise/counter-clockwise.</p>
+<p>Note, that knob scale actions can be enabled or disabled by the additional 'UI behavior' &rarr; 'Editable knob scale' option.</p>
 <p>To reset parameter to it's default value, left mouse button double click may be issued.</p>
+<p>Note that in most cases additional 'Parameter' widget that displays the actual value of the parameteris
+located nearby the knob . While the knob widget allows to adjust the value with some step, the 'Parameter'
+widget allows to set the precise value by double-clicking the displayed value and entering the new desired
+value by the keyboard.</p>
 
 <p style="text-align:center">Example showing knob controls:</p>
 <div class="images">