How to capture the order of user-selections from a multi-select picklist

Question

Right now SelectOption is sorting my selection of documents based on the TimeStamp of the document that has been uploaded, but I want to be able to have my list to be same order as what I select and not based on TimeStamp Here Ill try to explain this better.

So I am showing bunch of documents to the user. User will pick the documents in any order they would like. I need to get the same arbitrary order of the pick list that I have in docNames and pass it to BLST list . currently the system is sorting the BLST List based on TimeStamp, but I need it bast on docNames or (User) entry order not timestamp

public List<String> selectedDocuments {get; set;}
for (Document d :documents = [SELECT Id, Name , Body
                         from Document Where (FolderId =: UserInfo.getUserId() OR FolderId =: '00lG0000001bBXb') AND ContentType = 'application/pdf']){
            docNames.add(new SelectOption(d.Id,d.Name));

         }

for (Document d :documents = [SELECT Id, Name , Body
                         from Document Where Id in:selectedDocuments ]){

            BLST.add(Docments)


         }

Component

<apex:inputTextarea id="newDesc" value="{!Name}"/><p/>

            <apex:selectList value= "{!selectedDocuments}" multiselect="true">
                <apex:selectOptions value = "{!docNames}"/>
                </apex:selectList>
            <apex:commandButton action="{!Save}" value="Click" reRender="frm"/>

Answer 1

First of all, the VF selectList control has no documentation that says that order of items clicked will be the order of items presented in the corresponding controller's list variable.

As such, I can think of two alternatives and others may have additional suggestions

Option 1 Don't use the multi-select picklist

A more predictable-to-the-user interface might be one where the order of items to be presented is done through a drag-drop interface such as in jQuery UI sortable widget, Or, there's always the Netflix DVD Queue user interface where items to be ordered are given an entry box where the user can enter integers representing delivery order (yes, I'm old enough to remember DVDs on demand). It is hard to imagine that without some user feedback how click order actually commits the user to some resulting action sequence.

Option2 - Use a more powerful multi-select control like Chosen or Select2.

Some examples of this are covered in Stackoverflow. I've used these before (although not to retain click order) and they provide a nifty, space-saving multi-select picklist control - especially as compared to the OOB VF apex:inputField