Auto-focus on the Field input when clicking Add filter (#355)

Added Auto-focus on Add Filter Input

Done by setting the initial focus of the popover with the relevant selector

* correct autofocus

Signed-off-by: galangel <gal0angel@gmail.com>

* use class

Signed-off-by: galangel <gal0angel@gmail.com>

src/plugins/data/public/ui/filter_bar/filter_bar.tsx

@@ -121,7 +121,7 @@ function FilterBarUI(props: Props) {
           withTitle
           panelPaddingSize="none"
           ownFocus={true}
-          initialFocus=".filterEditor__hiddenItem"
+          initialFocus=".globalFilterEditor__fieldInput input"
           repositionOnScroll
         >
           <EuiFlexItem grow={false}>