diff --git a/app/XlsImporter/Foundation/Mapper/Activity.php b/app/XlsImporter/Foundation/Mapper/Activity.php
index 86bd4a3a5..0a4b115b2 100644
--- a/app/XlsImporter/Foundation/Mapper/Activity.php
+++ b/app/XlsImporter/Foundation/Mapper/Activity.php
@@ -321,7 +321,7 @@ public function defaultValues($data): void
             $secondary_reporter = '';
 
             if ($this->checkRowNotEmpty($row)) {
-                $elementActivityIdentifier = trim(Arr::get($row, 'activity_identifier'));
+                $elementActivityIdentifier = trim((string) Arr::get($row, 'activity_identifier'));
 
                 if (is_null($elementActivityIdentifier)) {
                     $this->globalErrors[] = 'Error detected on ' . $this->sheetName . ' sheet, cell A' . $this->rowCount . ': Identifier is missing.';
@@ -412,7 +412,7 @@ public function singleValuedFields($data): void
 
         foreach ($data as $index => $row) {
             if ($this->checkRowNotEmpty($row)) {
-                $elementActivityIdentifier = trim(Arr::get($row, 'activity_identifier'));
+                $elementActivityIdentifier = trim((string) Arr::get($row, 'activity_identifier'));
 
                 if (is_null($elementActivityIdentifier)) {
                     $this->globalErrors[] = 'Error detected on ' . $this->sheetName . ' sheet, cell A' . $this->rowCount . ': Identifier is missing.';
@@ -475,7 +475,7 @@ public function columnToFieldMapper($element, $data = []): void
                         $elementData = [];
                     }
 
-                    $elementActivityIdentifier = trim(Arr::get($row, 'activity_identifier') ?? $elementActivityIdentifier);
+                    $elementActivityIdentifier = trim((string) Arr::get($row, 'activity_identifier') ?? $elementActivityIdentifier);
                 }
 
                 foreach ($elementMapper as $xlsColumnName => $systemName) {
diff --git a/resources/assets/sass/component/_input.scss b/resources/assets/sass/component/_input.scss
index e2c936663..0eef68c73 100644
--- a/resources/assets/sass/component/_input.scss
+++ b/resources/assets/sass/component/_input.scss
@@ -256,41 +256,41 @@ label {
 }
 
 select.select2.default-value-indicator
-  + .select2
-  .selection
-  .select2-selection:not(:focus) {
++ .select2
+.selection
+.select2-selection:not(:focus) {
   border: 2px solid #3f9a7c;
   background-color: #3f9a7c15;
 }
 
 select.select2.default-value-indicator
-  + .select2
-  .selection
-  .select2-selection:not(:focus) {
++ .select2
+.selection
+.select2-selection:not(:focus) {
   border: 2px solid #3f9a7c;
   background-color: #3f9a7c15;
 }
 
 select.select2.default-value-indicator
-  + .select2
-  .selection
-  .select2-selection
-  .select2-selection__placeholder {
++ .select2
+.selection
+.select2-selection
+.select2-selection__placeholder {
   color: var(--bluecoral-50);
 }
 
 select.select2.default-value-indicator
-  + .select2.select2-container--open
-  .selection
-  .select2-selection {
++ .select2.select2-container--open
+.selection
+.select2-selection {
   border: 1px solid #a6b5ba;
   background-color: transparent;
 }
 
 select.select2.default-value-indicator
-  + .select2
-  .selection
-  .select2-selection.select2-selection--clearable {
++ .select2
+.selection
+.select2-selection.select2-selection--clearable {
   border: 1px solid #a6b5ba;
   background-color: transparent;
 }