Support submit buttons in Button groups

Change-Id: I9ab98dfdebe98f203697826bd8c3ed94dd2bffa2
diff --git a/dev/scss/main/buttongroup.scss b/dev/scss/main/buttongroup.scss
index 6a89297..85b2527 100644
--- a/dev/scss/main/buttongroup.scss
+++ b/dev/scss/main/buttongroup.scss
@@ -13,6 +13,7 @@
   &.button-panel,
   &.operators {
     > span,
+    input[type=submit],  
     a {
       @include choose-item;
       box-shadow:   $choose-box-shadow;
@@ -48,7 +49,11 @@
 
   &.button-panel {
     > span,
+    input[type=submit],  
     a {
+      margin-top: 0;
+      width: auto;
+      min-width: auto;
 
       > span.check {
         @include icon-font;
@@ -141,4 +146,4 @@
 
 .button-panel .button-icon {
   line-height: .7;
-}
\ No newline at end of file
+}