diff --git a/apps/desktop/src/components/diff/SchemaDiffDialog.vue b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
index 3c0b4db928..0ef81e662e 100644
--- a/apps/desktop/src/components/diff/SchemaDiffDialog.vue
+++ b/apps/desktop/src/components/diff/SchemaDiffDialog.vue
@@ -1283,7 +1283,7 @@ const targetConnectionInfo = computed(() => {
 
 <template>
   <Dialog v-model:open="open">
-    <DialogContent :class="['flex flex-col overflow-hidden', isMaximized ? 'min-w-0' : 'min-w-[800px] resize']" :portal-class="isMaximized ? 'p-0' : undefined" :style="dialogStyle" @interact-outside.prevent @escape-key-down="handleDialogEscape">
+    <DialogContent :class="['flex flex-col overflow-hidden dbx-schema-diff-dialog', isMaximized ? 'dbx-dialog-maximized min-w-0' : 'min-w-[800px] resize']" :portal-class="isMaximized ? 'p-0' : undefined" :style="dialogStyle" @interact-outside.prevent @escape-key-down="handleDialogEscape">
       <Button variant="ghost" size="icon-sm" class="absolute top-2 right-10 z-10" @click="toggleMaximize">
         <Maximize2 v-if="!isMaximized" class="w-4 h-4" />
         <Minimize2 v-else class="w-4 h-4" />
diff --git a/apps/desktop/src/components/ui/button/__tests__/buttonPressFeedback.spec.ts b/apps/desktop/src/components/ui/button/__tests__/buttonPressFeedback.spec.ts
new file mode 100644
index 0000000000..df3ab0740b
--- /dev/null
+++ b/apps/desktop/src/components/ui/button/__tests__/buttonPressFeedback.spec.ts
@@ -0,0 +1,43 @@
+// Source-contract guard for shared button press feedback.
+
+// Overview: desktop click responsiveness depends on buttons giving immediate
+// visual feedback while pressed. DOM `click` only fires on pointer-up, so a
+// press with zero visual delta reads as "the click did nothing" and users
+// retry or hold the button (~1s holds measured in click-probe sessions).
+//
+// Two guarantees keep that regression from re-appearing:
+//   1. Every button variant styles an `active:` pressed state, so pressing
+//      always changes something on screen before pointer-up.
+//   2. The pressed state must not move or scale the button (`scale-*` /
+//      `translate-*`). A moving hit target can land pointer-up outside the
+//      element it was pressed on, which genuinely drops the click.
+// Keep these assertions updated alongside the variant class strings.
+
+import { readFileSync } from "node:fs";
+import { describe, expect, it } from "vitest";
+
+const buttonVariantsSource = readFileSync(new URL("../index.ts", import.meta.url), "utf8");
+
+const VARIANTS = ["default", "outline", "secondary", "ghost", "destructive", "link"] as const;
+
+function variantClasses(variant: string): string {
+  const match = buttonVariantsSource.match(new RegExp(`${variant}:\\s*"([^"]+)"`));
+  expect(match, `variant "${variant}" exists in buttonVariants`).toBeTruthy();
+  return match![1];
+}
+
+describe("button press feedback guard", () => {
+  it.each(VARIANTS)("styles an active pressed state for the %s variant", (variant) => {
+    expect(variantClasses(variant)).toMatch(/(^|\s)active:/);
+  });
+
+  it.each(VARIANTS)("does not move the hit target while %s is pressed", (variant) => {
+    expect(variantClasses(variant)).not.toMatch(/active:(scale|translate|-translate)-/);
+  });
+
+  it("does not move the hit target from the shared base classes", () => {
+    const base = buttonVariantsSource.match(/cva\(\s*"([^"]+)"/);
+    expect(base).toBeTruthy();
+    expect(base![1]).not.toMatch(/active:(scale|translate|-translate)-/);
+  });
+});
diff --git a/apps/desktop/src/styles/__tests__/legacyWebviewFallback.spec.ts b/apps/desktop/src/styles/__tests__/legacyWebviewFallback.spec.ts
index 6c3891212e..8912120e53 100644
--- a/apps/desktop/src/styles/__tests__/legacyWebviewFallback.spec.ts
+++ b/apps/desktop/src/styles/__tests__/legacyWebviewFallback.spec.ts
@@ -34,6 +34,7 @@ const mainSource = readFileSync(new URL("../../main.ts", import.meta.url), "utf8
 const tabPresentationSource = readFileSync(new URL("../../lib/tabs/tabPresentation.ts", import.meta.url), "utf8");
 const editorGroupTabBarSource = readFileSync(new URL("../../components/layout/EditorGroupTabBar.vue", import.meta.url), "utf8");
 const appTabBarCssSource = readFileSync(new URL("../../components/layout/appTabBar.css", import.meta.url), "utf8");
+const schemaDiffDialogSource = readFileSync(new URL("../../components/diff/SchemaDiffDialog.vue", import.meta.url), "utf8");
 
 describe("legacy WebView CSS fallbacks", () => {
   it("keeps globals.css balanced and free of min-width media wrappers", () => {
@@ -547,6 +548,34 @@ describe("legacy WebView CSS fallbacks", () => {
     expect(globalsCss).toContain('html.dbx-legacy-webview input[type="number"]:not([class*="appearance-none"]):disabled::-webkit-inner-spin-button');
   });
 
+  it("keeps the schema diff dialog inline sizing working in legacy WebViews", () => {
+    // The shared DialogContent base carries max-w-sm, whose legacy !important cap
+    // outranks the dialog's inline width/max-width styles: the normal state then
+    // renders at its min-w floor and the maximize toggle collapses to 24rem wide.
+    // The rescue rules must sit after the max-w-* caps to win by source order.
+    const fallbackStart = globalsCss.indexOf("html.dbx-legacy-webview .sm\\:block");
+    const splitpanesStart = globalsCss.indexOf("/* Splitpanes */");
+    const fallback = globalsCss.slice(fallbackStart, splitpanesStart);
+    const maxWsmCap = fallback.indexOf('html.dbx-legacy-webview [data-slot="dialog-content"][class~="max-w-sm"]');
+    const normalRule = fallback.indexOf('html.dbx-legacy-webview [data-slot="dialog-content"].dbx-schema-diff-dialog {');
+    const maximizedRule = fallback.indexOf('html.dbx-legacy-webview [data-slot="dialog-content"].dbx-schema-diff-dialog.dbx-dialog-maximized {');
+
+    expect(fallbackStart).toBeGreaterThan(-1);
+    expect(splitpanesStart).toBeGreaterThan(fallbackStart);
+    expect(maxWsmCap).toBeGreaterThan(-1);
+    expect(normalRule).toBeGreaterThan(maxWsmCap);
+    expect(maximizedRule).toBeGreaterThan(normalRule);
+    expect(fallback.slice(normalRule, maximizedRule)).toContain("max-width: calc(100vw - 2rem) !important;");
+    expect(fallback.slice(normalRule, maximizedRule)).toContain("max-height: calc(var(--dbx-viewport-height) - 2rem) !important;");
+    expect(fallback.slice(maximizedRule)).toContain("width: calc(100vw - 2rem) !important;");
+    expect(fallback.slice(maximizedRule)).toContain("height: calc(var(--dbx-viewport-height) - 2rem) !important;");
+    expect(fallback.slice(maximizedRule)).toContain("max-width: none !important;");
+    expect(fallback.slice(maximizedRule)).toContain("max-height: none !important;");
+    expect(fallback.slice(maximizedRule)).toContain("border-radius: 0 !important;");
+    expect(schemaDiffDialogSource).toContain("'flex flex-col overflow-hidden dbx-schema-diff-dialog'");
+    expect(schemaDiffDialogSource).toContain("isMaximized ? 'dbx-dialog-maximized min-w-0' : 'min-w-[800px] resize'");
+  });
+
   it("keeps settings field stacks spaced in legacy WebViews", () => {
     const fallbackStart = editorSettingsDialogSource.indexOf("html.dbx-legacy-webview .settings-layout");
     const fallbackEnd = editorSettingsDialogSource.indexOf("@media (max-width: 760px)", fallbackStart);
diff --git a/apps/desktop/src/styles/globals.css b/apps/desktop/src/styles/globals.css
index 72f84b893d..75cbf3234a 100644
--- a/apps/desktop/src/styles/globals.css
+++ b/apps/desktop/src/styles/globals.css
@@ -1914,6 +1914,25 @@ html.dbx-legacy-webview [data-slot="dialog-content"][class*="max-w-[min(1080px"]
 html.dbx-legacy-webview [data-slot="dialog-content"][class*="max-w-[1800px]"] {
   max-width: 1800px !important;
 }
+
+/* The schema diff dialog sizes itself through inline width/height styles, which
+ * the max-w-sm !important cap above outranks in legacy WebViews — the dialog then
+ * renders at its min-w floor and the maximize toggle collapses to 24rem wide.
+ * Pin both states explicitly; these rules must stay after the max-w-* caps
+ * because they share specificity and win by source order. */
+html.dbx-legacy-webview [data-slot="dialog-content"].dbx-schema-diff-dialog {
+  max-width: calc(100vw - 2rem) !important;
+  max-height: calc(var(--dbx-viewport-height) - 2rem) !important;
+}
+
+html.dbx-legacy-webview [data-slot="dialog-content"].dbx-schema-diff-dialog.dbx-dialog-maximized {
+  width: calc(100vw - 2rem) !important;
+  height: calc(var(--dbx-viewport-height) - 2rem) !important;
+  max-width: none !important;
+  max-height: none !important;
+  border-radius: 0 !important;
+}
+
 html.dbx-legacy-webview [data-slot="dialog-content"].dbx-form-dialog {
   display: flex !important;
   flex-direction: column !important;