make search box in issue sidebar dropdown list always show when scrolling (#32576)

as title, replace #31597 after #32460 

---------

Signed-off-by: a1012112796 <1012112796@qq.com>

templates/repo/issue/sidebar/assignee_list.tmpl

@@ -16,6 +16,7 @@
 				<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_assignees"}}">
 			</div>
 			<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_assignees"}}</div>
+			<div class="scrolling menu">
 				{{range $data.CandidateAssignees}}
 					<a class="item muted" href="#" data-value="{{.ID}}">
 						<span class="item-check-mark">{{svg "octicon-check"}}</span>
@@ -24,6 +25,7 @@
 				{{end}}
 			</div>
 		</div>
+	</div>
 	<div class="ui list tw-flex tw-flex-row tw-gap-2">
 		<span class="item empty-list {{if $issueAssignees}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_assignees"}}</span>
 		{{range $issueAssignees}}

templates/repo/issue/sidebar/label_list.tmpl

@@ -17,6 +17,7 @@
 					<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_labels"}}">
 				</div>
 				<a class="item clear-selection" href="#">{{ctx.Locale.Tr "repo.issues.new.clear_labels"}}</a>
+				<div class="scrolling menu">
 					{{$previousExclusiveScope := "_no_scope"}}
 					{{range $data.RepoLabels}}
 						{{$exclusiveScope := .ExclusiveScope}}
@@ -36,6 +37,7 @@
 						{{$previousExclusiveScope = $exclusiveScope}}
 						{{template "repo/issue/sidebar/label_list_item" dict "Label" .}}
 					{{end}}
+				</div>
 			{{end}}
 		</div>
 	</div>

templates/repo/issue/sidebar/milestone_list.tmpl

@@ -20,6 +20,7 @@
 				</div>
 				<div class="divider"></div>
 				<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_milestone"}}</div>
+				<div class="scrolling menu">
 					{{if $data.OpenMilestones}}
 						<div class="divider"></div>
 						<div class="header">{{ctx.Locale.Tr "repo.issues.new.open_milestone"}}</div>
@@ -41,6 +42,7 @@
 				{{end}}
 			</div>
 		</div>
+	</div>
 
 	<div class="ui list">
 		<span class="item empty-list {{if $issueMilestone}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_milestone"}}</span>

templates/repo/issue/sidebar/project_list.tmpl

@@ -18,6 +18,7 @@
 			</div>
 			{{end}}
 			<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_projects"}}</div>
+			<div class="scrolling menu">
 				{{if $data.OpenProjects}}
 					<div class="divider"></div>
 					<div class="header">{{ctx.Locale.Tr "repo.issues.new.open_projects"}}</div>
@@ -38,6 +39,7 @@
 				{{end}}
 			</div>
 		</div>
+	</div>
 	<div class="ui list">
 		<span class="item empty-list {{if $issueProject}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_projects"}}</span>
 		{{if $issueProject}}

templates/repo/issue/sidebar/reviewer_list.tmpl

@@ -17,6 +17,7 @@
 					<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_reviewers"}}">
 				</div>
 			{{end}}
+			<div class="scrolling menu">
 				{{range $data.Reviewers}}
 					{{if .User}}
 						<a class="item muted {{if .Requested}}checked{{end}}" href="{{.User.HomeLink}}" data-value="{{.ItemID}}" data-can-change="{{.CanChange}}"
@@ -40,6 +41,7 @@
 				{{end}}
 			</div>
 		</div>
+	</div>
 
 	<div class="ui relaxed list flex-items-block tw-my-4">
 		<span class="item empty-list {{if or $data.OriginalReviews $data.CurrentPullReviewers}}tw-hidden{{end}}">

web_src/css/repo.css

@@ -66,6 +66,12 @@
   overflow-x: auto;
 }
 
+.issue-content-right .dropdown > .menu .item-secondary-info small {
+  display: block;
+  text-overflow: ellipsis;
+  overflow: hidden;
+}
+
 @media (max-width: 767.98px) {
   .issue-content-left,
   .issue-content-right {