diff --git a/browser/themes/linux/devtools/toolbox.css b/browser/themes/linux/devtools/toolbox.css
index 531c85fd35b8..e0a7683b51a8 100644
--- a/browser/themes/linux/devtools/toolbox.css
+++ b/browser/themes/linux/devtools/toolbox.css
@@ -163,6 +163,7 @@
   background-repeat: no-repeat;
   background-position: left, right;
   border-right: 1px solid hsla(206,37%,4%,.45);
+  -moz-box-align: center;
 }
 
 .devtools-tab > image {
@@ -170,6 +171,7 @@
   -moz-margin-end: 6px;
   -moz-margin-start: 16px;
   opacity: 0.6;
+  max-height: 16px;
 }
 
 .devtools-tab > label {
diff --git a/browser/themes/osx/devtools/toolbox.css b/browser/themes/osx/devtools/toolbox.css
index f43646f96911..4c6524d90a62 100644
--- a/browser/themes/osx/devtools/toolbox.css
+++ b/browser/themes/osx/devtools/toolbox.css
@@ -152,6 +152,7 @@
   background-repeat: no-repeat;
   background-position: left, right;
   border-right: 1px solid hsla(206,37%,4%,.45);
+  -moz-box-align: center;
 }
 
 .devtools-tab > image {
diff --git a/browser/themes/windows/devtools/toolbox.css b/browser/themes/windows/devtools/toolbox.css
index 46fadd0a7847..e1ac3a6430f4 100644
--- a/browser/themes/windows/devtools/toolbox.css
+++ b/browser/themes/windows/devtools/toolbox.css
@@ -165,6 +165,7 @@
   background-position: left, right;
   border-top: 1px solid #060a0d;
   border-right: 1px solid hsla(206,37%,4%,.45);
+  -moz-box-align: center;
 }
 
 .devtools-tab > image {