It is still an issue for RTL.

I am not surprised this is a bad fix

I have tested this item ✅ successfully on 23036c0

For RTL, the arrow needs to be moved to the left.

for rtl it needs to load a different image

I have tested this item ✅ successfully on 23036c0

I found it on /administrator/index.php?option=com_plugins

RTC

The rtl image has been created in #27387

I guess remains to create a new variable and correct the rtl where the ltr variable is used.
Will do if not done here.

will check tomorrow

removed RTC

Hmm, in fact I was mistaken.
We do not have the equivalent of select-bg-active.svg for RTL.
We have only the equivalent of select-bg.svg as select-bg-rtl.svg

NOTE: that last one is not present in installation/template/images/

  [dir=rtl] .custom-select {
    padding: 0.6rem 1rem 0.6rem 4rem;
    background-position-x: 0%;
    background-image: url(../images/select-bg-rtl.svg); }
```
 which makes the class useless in 
`/installation/template/css/template.css` and `template-rtl.css`

But as it looks like RTL has other issues in installation, it's just one of the aspects.

Just came back to say you were mistaken about the image existing and I see you realised that as well.

I don't have the time, energy or desire to work on that so either accept this PR as is and create a new one for RTL or not.

Here is the .diff including this PR and the new image

diff --git a/administrator/templates/atum/images/select-bg-active-rtl.svg b/administrator/templates/atum/images/select-bg-active-rtl.svg
new file mode 100644
index 0000000..06c38dc
--- /dev/null
+++ b/administrator/templates/atum/images/select-bg-active-rtl.svg
@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1854.54 295" preserveAspectRatio="xMinYMid" width="1854.54" height="295"><path d="m14.47 145.7 6.898 6.899c0.102 0.101 0.199 0.101 0.3 0.101 0.102 0 0.2 0 0.302-0.101l6.898-6.899c0.102-0.1 0.102-0.2 0.102-0.3s0-0.2-0.102-0.3l-0.7-0.7c-0.101-0.1-0.198-0.1-0.3-0.1-0.101 0-0.2 0-0.301 0.1l-5.8 5.8-5.801-5.8c-0.101-0.1-0.199-0.1-0.301-0.1-0.101 0-0.199 0-0.301 0.1l-0.699 0.7c-0.101 0.1-0.101 0.2-0.101 0.3-0.294 0.1-0.194 0.2-0.094 0.3z" fill="#fff"/></svg>
\ No newline at end of file
diff --git a/administrator/templates/atum/scss/_variables.scss b/administrator/templates/atum/scss/_variables.scss
index d638e4f..9b70eee 100644
--- a/administrator/templates/atum/scss/_variables.scss
+++ b/administrator/templates/atum/scss/_variables.scss
@@ -214,5 +214,6 @@
 $custom-select-bg-size:              116rem;
 $custom-select-indicator:            url(../images/select-bg.svg);
-$custom-select-indicator-active:     url(../images/select-bg-active.svg);
+$custom-select-indicator-active:     url(../../../images/select-bg-active.svg);
+$custom-select-indicator-active-rtl: url(../../../images/select-bg-active-rtl.svg);
 $custom-select-background:           $custom-select-indicator no-repeat right center / $custom-select-bg-size; // Used so we can have multiple background elements (e.g., arrow and feedback icon)
 $custom-select-box-shadow:           $atum-box-shadow;
diff --git a/administrator/templates/atum/scss/system/searchtools/searchtools.scss b/administrator/templates/atum/scss/system/searchtools/searchtools.scss
index ba85aad..1f53104 100644
--- a/administrator/templates/atum/scss/system/searchtools/searchtools.scss
+++ b/administrator/templates/atum/scss/system/searchtools/searchtools.scss
@@ -90,4 +90,8 @@
         background: $custom-select-bg $custom-select-indicator-active no-repeat right center;
         background-size: $custom-select-bg-size;
+
+        [dir=rtl] & {
+          background: $custom-select-bg $custom-select-indicator-active-rtl no-repeat left center;
+        }
       }
 

Just let me know if you can modify this PR or not.

The diff wouldnt apply for some reason but I have applied it manually - thanks

I have tested this item ✅ successfully on 0c3b8c2

@Quy @Fedik
Please test again, in RTL.

I have tested this item ✅ successfully on 0c3b8c2

RTC

Thanks

progress - thanks