[Pale-Moon] Issue #1772 - Only refresh tabs in restore-on-demand mode.

Only enable the refresh modes for session store cache behavior if the
currently selected mode is "Don't restore tabs until selected" to
prevent known issues with restoring too many tabs from the network
concurrently.

This resolves #1772

application/palemoon/components/sessionstore/SessionStore.jsm

@@ -3236,19 +3236,24 @@ var SessionStoreInternal = {
         // instead of gotoIndex. See bug 597315.
         browser.webNavigation.sessionHistory.getEntryAtIndex(activeIndex, true);
         browser.webNavigation.sessionHistory.reloadCurrentEntry();
-        // If the user prefers it, bypass cache and always load from the network.
-        let flags = Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
-        switch (this._cacheBehavior) {
-          case 2: // hard refresh
-            flags = Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_PROXY |
-                    Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_CACHE;
-            browser.webNavigation.reload(flags);
-            break;
-          case 1: // soft refresh
-            browser.webNavigation.reload(flags);
-            break;
-          default: // 0 or other: use cache, so do nothing.
-            break;
+        // If the user prefers it, bypass cache and always load from the network,
+        // but only if restoring on demand, to prevent request flooding (since
+        // reloading will override the max tabs to restore concurrently mechanism).
+        // See Issue #1772
+        if (restoreOnDemand) {
+          let flags = Ci.nsIWebNavigation.LOAD_FLAGS_NONE;
+          switch (this._cacheBehavior) {
+            case 2: // hard refresh
+              flags = Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_PROXY |
+                      Ci.nsIWebNavigation.LOAD_FLAGS_BYPASS_CACHE;
+              browser.webNavigation.reload(flags);
+              break;
+            case 1: // soft refresh
+              browser.webNavigation.reload(flags);
+              break;
+            default: // 0 or other: use cache, so do nothing.
+              break;
+          }
         }
       }
       catch (ex) {