impr(funbox): improve error message when funbox cannot be set with current config

Closes #4617

frontend/src/ts/test/funbox/funbox-validation.ts

@@ -161,7 +161,7 @@ export function canSetFunboxWithConfig(
   } else {
     funboxToCheck += "#" + funbox;
   }
-  let errorCount = 0;
+  const errors = [];
   for (const [configKey, configValue] of Object.entries(config)) {
     if (
       !canSetConfigWithCurrentFunboxes(
@@ -171,18 +171,29 @@ export function canSetFunboxWithConfig(
         true
       )
     ) {
-      errorCount += 1;
+      errors.push({
+        key: configKey,
+        value: configValue,
+      });
     }
   }
-  if (errorCount > 0) {
+  if (errors.length > 0) {
+    const errorStrings = [];
+    for (const error of errors) {
+      errorStrings.push(
+        `${Misc.capitalizeFirstLetter(
+          Misc.camelCaseToWords(error.key)
+        )} cannot be set to ${error.value}.`
+      );
+    }
     Notifications.add(
-      `You can't enable ${funbox.replace(
-        /_/g,
-        " "
-      )} with currently active config.`,
+      `You can't enable ${funbox.replace(/_/g, " ")}:<br>${errorStrings.join(
+        "<br>"
+      )}`,
       0,
       {
         duration: 5,
+        allowHTML: true,
       }
     );
     return false;