I had this problem on my three sharepoint sites and i manage to resolve this problem by modifying CSS code (cf http://social.msdn.microsoft.com/Forums/en-US/sharepoint2010general/thread/64796605-bcbb-4a87-9d8d-9d609579577f/) on two of them.
I don't know why this doesn't work on my third one which has same updates, same CSS and same html code... I tried several solutions such as adding indesign="true"(this can't be use because the lists got more than 75 columns). cf http://www.codeproject.com/Articles/194254/Advanced-fixing-SharePoint-2010-large-lookup-dropd
The only solutions i found required javascript but i don't really want to use it...
If someone have another solution to propose, i would really appreciate.
EDIT: Thanks to moontear i found something quite great. I replace the beginning of the script by : $(document).ready(function () {
$('.ms-lookuptypeintextbox').each(function(){
OverrideDropDownList($(this).attr('title'));
});
// Main Function
function OverrideDropDownList(columnName) {
...
By this way, i just have to include the script and don't care about what columns got problems...
This script seems to be quite great to solve this problem... Thank you moontear for your comment The original script come from : http://sharepointegg.blogspot.de/2010/10/fixing-sharepoint-2010-lookup-drop-down.html
$(document).ready(function () {
$('.ms-lookuptypeintextbox').each(function(){
OverrideDropDownList($(this).attr('title'));
});
// Main Function
function OverrideDropDownList(columnName) {
// Construct a drop down list object
var lookupDDL = new DropDownList(columnName);
// Do this only in complex mode...
if (lookupDDL.Type == "C") {
// Hide the text box and drop down arrow
lookupDDL.Obj.css('display', 'none');
lookupDDL.Obj.next("img").css('display', 'none');
// Construct the simple drop down field with change trigger
var tempDDLName = "tempDDLName_" + columnName;
if (lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").length == 0) {
lookupDDL.Obj.parent().append("<select name='" + tempDDLName + "' id='" + tempDDLName + "' title='" + tempDDLName + "'></select>");
lookupDDL.Obj.parent().find("select[ID='" + tempDDLName + "']").bind("change", function () {
updateOriginalField(columnName, tempDDLName);
});
}
// Get all the options
var splittedChoices = lookupDDL.Obj.attr('choices').split("|");
// get selected value
var hiddenVal = $('input[name=' + lookupDDL.Obj.attr("optHid") + ']').val();
if (hiddenVal == "0") {
hiddenVal = lookupDDL.Obj.attr("value")
}
// Replacing the drop down object with the simple drop down list
lookupDDL = new DropDownList(tempDDLName);
// Populate the drop down list
for (var i = 0; i < splittedChoices.length; i++) {
var optionVal = splittedChoices[i];
i++;
var optionId = splittedChoices[i];
var selected = (optionId == hiddenVal) ? " selected='selected'" : "";
lookupDDL.Obj.append("<option" + selected + " value='" + optionId + "'>" + optionVal + "</option>");
}
}
}
// method to update the original and hidden field.
function updateOriginalField(child, temp) {
var childSelect = new DropDownList(child);
var tempSelect = new DropDownList(temp);
// Set the text box
childSelect.Obj.attr("value", tempSelect.Obj.find("option:selected").val());
// Get Hidden ID
var hiddenId = childSelect.Obj.attr("optHid");
// Update the hidden variable
$('input[name=' + hiddenId + ']').val(tempSelect.Obj.find("option:selected").val());
}
// just to construct a drop down box object. Idea token from SPServces
function DropDownList(colName) {
// Simple - when they are less than 20 items
if ((this.Obj = $("select[Title='" + colName + "']")).html() != null) {
this.Type = "S";
// Compound - when they are more than 20 items
} else if ((this.Obj = $("input[Title='" + colName + "']")).html() != null) {
this.Type = "C";
// Multi-select: This will find the multi-select column control on English and most other languages sites where the Title looks like 'Column Name possible values'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title^='" + colName + " ']")).html() != null) {
this.Type = "M";
// Multi-select: This will find the multi-select column control on a Russian site (and perhaps others) where the Title looks like '????????? ????????: Column Name'
} else if ((this.Obj = $("select[ID$='SelectCandidate'][Title$=': " + colName + "']")).html() != null) {
this.Type = "M";
} else
this.Type = null;
} // End of function dropdownCtl
});