Resolve "Left panel is resized when switching between left panel tabs"

Closes #425 (closed)

frontend-js/src/main/css/global.css

@@ -386,10 +386,9 @@ table.minerva-window-drug-table td {
 
 .minerva-left-panel {
     position: relative;
-    float: left;
+    flex: 0 0 357px;
     border: none;
     background-color: #ffffff;
-    width: 357px;
     height: 100%;
 }