feat(dropdown): optional keeping the searchterm

New option keepSearchTerm for multiple search selection dropdowns. This (almost) reflects the current SUI behavior (which we fixed already)

The list stays filtered
The search term is not removed on item selection (to make it clear why the list is still filtered on selection)
This PR also removes the completely unused glyphWidth setting. This is all done in CSS instead of JS (not even in current SUI) and we fixed the search width glyph calculation already by #145 which in turn closes Semantic-Org/Semantic-UI#6655

src/definitions/modules/dropdown.js

@@ -1407,11 +1407,13 @@
                                     if (settings.allowAdditions) {
                                         module.remove.userAddition();
                                     }
-                                    module.remove.filteredItem();
+                                    if (!settings.keepSearchTerm) {
+                                        module.remove.filteredItem();
+                                        module.remove.searchTerm();
+                                    }
                                     if (!module.is.visible() && $target.length > 0) {
                                         module.show();
                                     }
-                                    module.remove.searchTerm();
                                     if (!module.is.focusedOnSearch() && skipRefocus !== true) {
                                         module.focusSearch(true);
                                     }
@@ -1597,7 +1599,9 @@
                                         module.verbose('Selecting item from keyboard shortcut', $selectedItem);
                                         module.event.item.click.call($selectedItem, event);
                                         if (module.is.searchSelection()) {
-                                            module.remove.searchTerm();
+                                            if (!settings.keepSearchTerm) {
+                                                module.remove.searchTerm();
+                                            }
                                             if (module.is.multiple()) {
                                                 $search.trigger('focus');
                                             }
@@ -1814,7 +1818,7 @@
                             ? value
                             : text;
                         if (module.can.activate($(element))) {
-                            module.set.selected(value, $(element));
+                            module.set.selected(value, $(element), false, settings.keepSearchTerm);
                             if (!module.is.multiple() && !(!settings.collapseOnActionable && $(element).hasClass(className.actionable))) {
                                 module.hideAndClear();
                             }
@@ -2464,7 +2468,7 @@
                             valueIsSet       = searchValue !== ''
                         ;
                         if (isMultiple && hasSearchValue) {
-                            module.verbose('Adjusting input width', searchWidth, settings.glyphWidth);
+                            module.verbose('Adjusting input width', searchWidth);
                             $search.css('width', searchWidth + 'px');
                         }
                         if (hasSearchValue || (isSearchMultiple && valueIsSet)) {
@@ -2763,7 +2767,7 @@
                             return false;
                         }
                         module.debug('Setting selected menu item to', $selectedItem);
-                        if (module.is.multiple()) {
+                        if (module.is.multiple() && !keepSearchTerm) {
                             module.remove.searchWidth();
                         }
                         if (module.is.single()) {
@@ -4006,6 +4010,7 @@
         forceSelection: false, // force a choice on blur with search selection
 
         allowAdditions: false, // whether multiple select should allow user added values
+        keepSearchTerm: false, // whether the search value should be kept and menu stays filtered on item selection
         ignoreCase: false, // whether to consider case sensitivity when creating labels
         ignoreSearchCase: true, // whether to consider case sensitivity when filtering items
         hideAdditions: true, // whether or not to hide special message prompting a user they can enter a value
@@ -4025,8 +4030,6 @@
         duration: 200, // duration of transition
         displayType: false, // displayType of transition
 
-        glyphWidth: 1.037, // widest glyph width in em (W is 1.037 em) used to calculate multiselect input width
-
         headerDivider: true, // whether option headers should have an additional divider line underneath when converted from <select> <optgroup>
 
         collapseOnActionable: true, // whether the dropdown should collapse upon selection of an actionable item