Rich UI memory management

Two memory-management functions are available for avoiding memory leaks. The leaks slow your application and can cause the browser to crash.

The issue arises primarily if you declare a widget or embedded handler within a function. These in-function declarations allocate memory at run time. Even after the function ends, the browser returns the memory to the operating system only after the user has closed the browser tab.

Each of the memory-management functions requests that the browser return memory. The browser typically fulfills the request after a delay, but while the application is still running.

The functions are as follows:

UtilLib.destroyRUIHandler (ruiHandler Any in) requests removal of the widgets in the specified handler, in any handlers embedded in the specified handler, and in any handlers embedded in the embedded handlers, to any level of depth. The input value must be a Rich UI handler.
UtilLib.destroyWidget (myWidget Widget in) requests removal of the specified widget.
UtilLib.destroyWidgetChildren (myWidget Widget in) requests removal of the children of the specified widget

None of those functions returns a value.

If you are affected by the issue just described, consider these coding conventions:

Use the memory-management functions to return allocated memory that is no longer needed.
In a function, use anonymous declarations only if you have access to the named container, which is the named widget that embeds the anonymous declaration.
For example, consider a tooltip, which is a box that is displayed when the user hovers over an area on the page. A tooltip provider is a function that returns the box to be displayed, and the code for that function might be as follows:
```
Function myProvider (widget any in) returns(Box) 
   return (new Box {children = [new Button{text = "Memory leak"}]});
end
```
In this example, the tooltip provider creates a box that cannot be referenced from outside the function, and the box itself includes an anonymous widget. The inability to reference the box means that you cannot pass the box or its anonymous child to a memory-management function.
To avoid the problem in this example, declare the box outside the tooltip provider:
```
myBox Box{};
Function myProvider (widget any in) returns(Box) 
   myBox.children = [ new Button{text = "Problem solved"} ];       
   return(myBox);
end
```
Elsewhere in your application, you can now pass myBox to a memory-management function, as in the following example:
```
UtilLib.destroyWidgetChildren(myBox);
```
After you use the removeChild or removeChildren function to remove widgets from the DOM tree, remove the memory that was allocated for those widgets. For details on those functions, see “Widget properties and functions.”