add page for E040

E040.md

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+# E040
+
+## `.hide` should not be used on `.modal` in Bootstrap v3.
+
+In Bootstrap v3, modals are hidden by default by virtue of the `.modal` class. There is no need to add `.hide` to a `.modal`, and in fact adding `.hide` will interfere with proper showing of the modal, so it should not be done.
+
+`.modal.hide` was previously required in old Bootstrap v2, but this is no longer the case in Bootstrap v3. The markup required for modals has changed significantly between v2 and v3, and modal examples for Bootstrap v2 should therefore not be followed when using Bootstrap v3.
+
+Wrong:
+```html
+<div class="modal hide">
+  ...
+</div>
+```
+
+Right:
+```html
+<div class="modal fade">
+  ...
+</div>
+```
+
+Also Right:
+```
+<!--Modal without show/hide animation-->
+<div class="modal">
+  ...
+</div>
+```