Further improve AutoScroll docs

Author: owen-m1

plugins/AutoScroll/README.md

@@ -53,7 +53,12 @@ Useful when you have custom scrollbar with dedicated scroll function.
 Defines a function that will be used for autoscrolling. Sortable uses el.scrollTop/el.scrollLeft by default. Set this option if you wish to handle it differently.
 This function should return `'continue'` if it wishes to allow Sortable's native autoscrolling, otherwise Sortable will not scroll anything if this option is set.
 
-**Note that this option will only work on all browsers/devices if Sortable's `forceFallback: true` option is set.**
+**Note that this option will only work if Sortable's autoscroll function is invoked.**
+
+It is invoked if any of the following are true:
+ - The `forceFallback: true` option is set
+ - It is a mobile device
+ - The browser is either Safari, Internet Explorer, or Edge
 
 
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@@ -62,7 +67,12 @@ This function should return `'continue'` if it wishes to allow Sortable's native
 #### `scrollSensitivity` option
 Defines how near the mouse must be to an edge to start scrolling.
 
-**Note that this option will only work on all browsers/devices if Sortable's `forceFallback: true` option is set.**
+**Note that this option will only work if Sortable's autoscroll function is invoked.**
+
+It is invoked if any of the following are true:
+ - The `forceFallback: true` option is set
+ - It is a mobile device
+ - The browser is either Safari, Internet Explorer, or Edge
 
 
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@@ -71,8 +81,12 @@ Defines how near the mouse must be to an edge to start scrolling.
 #### `scrollSpeed` option
 The speed at which the window should scroll once the mouse pointer gets within the `scrollSensitivity` distance.
 
-**Note that this option will only work on all browsers/devices if Sortable's `forceFallback: true` option is set.**
+**Note that this option will only work if Sortable's autoscroll function is invoked.**
 
+It is invoked if any of the following are true:
+ - The `forceFallback: true` option is set
+ - It is a mobile device
+ - The browser is either Safari, Internet Explorer, or Edge
 
 ---