Fix position of controls

[ci skip]

app/assets/stylesheets/content/work_packages/timelines/_timelines.sass

@@ -26,7 +26,6 @@
   position: relative
   width: 100%
   height: 100%
-  border-left: 5px solid #888
 
 .wp-table-timeline--header
   height: $generic-table--header-height
@@ -36,6 +35,15 @@
   background: white
   z-index: 300
 
+// Outer container
+// Must not be relative positioned for the controls to work
+.wp-table-timeline--outer
+  height: 100%
+
+// Left border for the timeline
+.work-packages-split-view--left-timeline
+  border-left: 5px solid #888
+
 // Ensure the height of table and timeline rows
 .wp-timeline-cell,
 .wp-table--row

app/assets/stylesheets/layout/_work_package_table.sass

@@ -80,6 +80,9 @@
   flex: 2
   display: flex
   overflow: hidden
+  // Required for any absolute positioned elements within the viewport
+  // (e.g., timeline controls)
+  position: relative
 
 // TABLE half
 .work-packages-split-view--left-table

frontend/app/components/wp-table/timeline/container/wp-timeline-container.html

@@ -1,6 +1,8 @@
-<div class="wp-table-timeline--container">
-  <wp-timeline-header></wp-timeline-header>
-  <wp-timeline-grid></wp-timeline-grid>
+<div class="wp-table-timeline--outer">
   <wp-timeline-controls></wp-timeline-controls>
-  <div class="wp-table-timeline--body"></div>
+  <div class="wp-table-timeline--container">
+    <wp-timeline-header></wp-timeline-header>
+    <wp-timeline-grid></wp-timeline-grid>
+    <div class="wp-table-timeline--body"></div>
+  </div>
 </div>