TYPO3 Core

can reproduce this

Problem is that initFlashUploader() is not defined in global scope, but only in a local, reachable from the upload-button on top of file_list.
This initFlashUploader() also takes event as parameter, not path, so it differs a bit.

I just solved the related bug for DAM and think that it's not a problem to solve this bug. If you're OK with my approach I will provide patches for the core. Currently we have this JavaScript in the file list:

if ($GLOBALS['BE_USER']->uc['enableFlashUploader']) {

    $this->doc->JScodeArray['flashUploader'] = '
        if (top.TYPO3.FileUploadWindow.isFlashAvailable()) {
            document.observe("dom:loaded", function() {
                    // monitor the button
                $("button-upload").observe("click", initFlashUploader);
                    function initFlashUploader(event) {
                        // set the page specific options for the flashUploader
                    var flashUploadOptions = {
                        uploadURL:           top.TS.PATH_typo3 + "ajax.php",
                        uploadFileSizeLimit: "' . t3lib_div::getMaxUploadFileSize() . '",
                        uploadFileTypes: {
                            allow:  "' . $GLOBALS['TYPO3_CONF_VARS']['BE']['fileExtensions']['webspace']['allow'] . '",
                            deny: "' . $GLOBALS['TYPO3_CONF_VARS']['BE']['fileExtensions']['webspace']['deny'] . '" 
                        },
                        uploadFilePostName:  "upload_1",
                        uploadPostParams: {
                            "file[upload][1][target]": "' . $this->id . '",
                            "file[upload][1][data]": 1,
                            "file[upload][1][charset]": "utf-8",
                            "ajaxID": "TYPO3_tcefile::process" 
                        }
                    };

                        // get the flashUploaderWindow instance from the parent frame
                    var flashUploader = top.TYPO3.FileUploadWindow.getInstance(flashUploadOptions);
                        // add an additional function inside the container to show the checkbox option
                    var infoComponent = new top.Ext.Panel({
                        autoEl: { tag: "div" },
                        height: "auto",
                        bodyBorder: false,
                        border: false,
                        hideBorders: true,
                        cls: "t3-upload-window-infopanel",
                        id: "t3-upload-window-infopanel-addition",
                        html: \'<label for="overrideExistingFilesCheckbox"><input id="overrideExistingFilesCheckbox" type="checkbox" onclick="setFlashPostOptionOverwriteExistingFiles(this);" />\' + top.String.format(top.TYPO3.LLL.fileUpload.infoComponentOverrideFiles) + \'</label>\'
                    });
                    flashUploader.add(infoComponent);
                        // do a reload of this frame once all uploads are done
                    flashUploader.on("totalcomplete", function() {
                        window.location.reload();
                    });

                        // this is the callback function that delivers the additional post parameter to the flash application
                    top.setFlashPostOptionOverwriteExistingFiles = function(checkbox) {
                        var uploader = top.TYPO3.getInstance("FileUploadWindow");
                        if (uploader.isVisible()) {
                            uploader.swf.addPostParam("overwriteExistingFiles", (checkbox.checked == true ? 1 : 0));
                        }
                    };

                    event.stop();
                };
            });
        }
    ';
}

This means that the function function initFlashUploader is only available if the event was triggered from a click to a <a id="button-upload">. We can put this function before event observer and it will also be available for direct calling from the context menu.

As for the event or path thing we can take a switch: If it's just a mouse click the the <a>-Tag, we use the target as currently ($this->id), if not, we decode the path and use it:

var target;
if (typeof(event)=="string") {
    target = decodeURIComponent(event);
    alert(target);
} else {
    target = "' . $this->id . '";
}

What do you think?

Patch set 1 for branch TYPO3_6-0 has been pushed to the review server.
It is available at https://review.typo3.org/19211