diff --git a/src/components/library/molecules/Dropdown/Dropdown.module.scss b/src/components/library/molecules/Dropdown/Dropdown.module.scss
index 6ae6fdc6..283cac88 100644
--- a/src/components/library/molecules/Dropdown/Dropdown.module.scss
+++ b/src/components/library/molecules/Dropdown/Dropdown.module.scss
@@ -42,6 +42,12 @@
 
     .text {
       flex: 1;
+      // The trigger is a fixed-height row, so a long selected label has to
+      // truncate — wrapping would spill out of the bottom of the control.
+      min-width: 0;
+      overflow: hidden;
+      white-space: nowrap;
+      text-overflow: ellipsis;
       text-align: left;
     }
 
@@ -98,6 +104,12 @@
   position: fixed;
   right: auto;
   z-index: 1500;
+  // `.menu` is `width: 100%`, which under `position: fixed` resolves against
+  // the viewport. Size to the longest option instead; the inline min-width
+  // keeps the menu at least as wide as the trigger (compact pill triggers
+  // would otherwise crush option labels into a one-word-per-line column) and
+  // the inline max-width keeps it inside the viewport.
+  width: max-content;
 }
 
 .optionWrapper {
@@ -138,6 +150,14 @@
   }
 }
 
+// Shelf and library names can be a single long token ("Crime/Detective"), and
+// the menu is `overflow: visible` so an unbroken one paints over whatever sits
+// behind the dropdown. Break it instead.
+.optionLabel {
+  min-width: 0;
+  overflow-wrap: anywhere;
+}
+
 .subArrow {
   flex-shrink: 0;
   transform: rotate(0deg);
diff --git a/src/components/library/molecules/Dropdown/Dropdown.tsx b/src/components/library/molecules/Dropdown/Dropdown.tsx
index 80330446..647272b1 100644
--- a/src/components/library/molecules/Dropdown/Dropdown.tsx
+++ b/src/components/library/molecules/Dropdown/Dropdown.tsx
@@ -112,7 +112,11 @@ export function Dropdown(props: DropdownProps): JSX.Element {
           ? {
               top: menuPos.top,
               left: menuPos.left,
-              width: menuPos.width,
+              // Never narrower than the trigger, never wider than the room
+              // left of the viewport's right edge, and capped so a long shelf
+              // name can't stretch the menu across the whole screen.
+              minWidth: menuPos.width,
+              maxWidth: `min(320px, calc(100vw - ${menuPos.left + 8}px))`,
               transform:
                 menuPos.placement === 'top' ? 'translateY(-100%)' : undefined,
             }
@@ -167,7 +171,12 @@ export function Dropdown(props: DropdownProps): JSX.Element {
                   </div>
                 </>
               ) : (
-                <Text variant={TypographyVariant.TextBase}>{option.label}</Text>
+                <Text
+                  variant={TypographyVariant.TextBase}
+                  className={styles.optionLabel}
+                >
+                  {option.label}
+                </Text>
               )}
               {hasSubOptions ? (
                 <ArrowIcon
@@ -198,7 +207,10 @@ export function Dropdown(props: DropdownProps): JSX.Element {
                     onKeyDown={activateOnKey(() => handleSubSelect(sub.value))}
                     aria-label={`Select ${sub.label}`}
                   >
-                    <Text variant={TypographyVariant.TextBase}>
+                    <Text
+                      variant={TypographyVariant.TextBase}
+                      className={styles.optionLabel}
+                    >
                       {sub.label}
                     </Text>
                     {value === sub.value && (
diff --git a/src/components/library/organisms/ObjectOverviewModal/ObjectOverviewModal.module.scss b/src/components/library/organisms/ObjectOverviewModal/ObjectOverviewModal.module.scss
index 6469c808..4bdc0fb5 100644
--- a/src/components/library/organisms/ObjectOverviewModal/ObjectOverviewModal.module.scss
+++ b/src/components/library/organisms/ObjectOverviewModal/ObjectOverviewModal.module.scss
@@ -363,6 +363,9 @@
 // the Shelf settings-trigger override). Compact pill, not a full-width field.
 .moveToTrigger {
   width: fit-content !important;
+  // The pill hugs its label, so a long shelf name would push it past the
+  // modal's edge; cap it and let the trigger's own ellipsis do the rest.
+  max-width: 100%;
   padding: 7px 12px !important;
   background: var(--white) !important;
   border: 1px solid var(--beige) !important;