bad behaviour on editor (phtml)

Can anyone explain me why I see the changes of colors on white spaces editing a document?
Look at the image annexed:

furthermore, when I do a cut&paste or copy&paste on some areas, the pasted area doesn't contains all the copied initially.
My system:
PhpStorm 7.1.3,
Linux Ubuntu 14.04,
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)

here the text format:
-------------------------------------------------------------------------------------------------------------------------------------
$h = new Zend_Form_Decorator_Form();
$h->setElement($form);
?>
<div ></div>
<div >
    <?php echo $h->render(false) ?>
    <div>
        <div ><label for=title"><?= $form->title->getLabel() ?></label></div>
        <div ><?= $form->title ?></div>
    </div>
    <div>
        <div ><label for="layout_id"><?= $form->layout_id->getLabel() ?></label></div>
        <div ><?= $form->layout_id ?></div>
    </div>
    <div ></div>
    <hr/>
    <div>

        <div ><p>Target</p></div>
        <div ><p>Item</p></div>
    </div>
    <div ></div>
    <div id="targets">
    <?php foreach ($form->getTargets() as $r): ?>
        <?= $form->$r ?>
    <?php endforeach; ?>
    </div>
    <div ></div>
    <?= "</form>" ?>
</div>

<div id="wg-grid-dialog" title="Seleziona articolo" >
    <table id="wg-grid-table">
        <tr>
            <td/>
        </tr>
    </table>
    <div id="wg-grid-pager"></div>
</div>