diff --git a/package.json b/package.json
index 9bc92b70936e5e0f361c7fa99cbcbf9bde24d3aa..313fc12e66ef8d9cbc3a6df86e72b72ba219d763 100644
--- a/package.json
+++ b/package.json
@@ -103,7 +103,7 @@
     "redux-throttle": "0.1.1",
     "rimraf": "^2.6.1",
     "scratch-audio": "0.1.0-prerelease.20181023202904",
-    "scratch-blocks": "0.1.0-prerelease.1544667276",
+    "scratch-blocks": "0.1.0-prerelease.1544721188",
     "scratch-l10n": "3.1.20181213173343",
     "scratch-paint": "0.2.0-prerelease.20181212232948",
     "scratch-render": "0.1.0-prerelease.20181212233715",
diff --git a/src/components/alerts/alert.css b/src/components/alerts/alert.css
index 2f5b8bd6c526d190b81248988df26e5241c2fa48..8e5d56296e6a40c29a1d195af377b652408b05e2 100644
--- a/src/components/alerts/alert.css
+++ b/src/components/alerts/alert.css
@@ -7,9 +7,12 @@
     display: flex;
     flex-direction: row;
     overflow: hidden;
-    justify-content: space-between;
+    justify-content: flex-start;
     border-radius: $space;
-    padding: $space;
+    padding-top: .875rem;
+    padding-bottom: .875rem;
+    padding-left: 1rem;
+    padding-right: 1rem;
     margin-bottom: 7px;
     min-height: 1.5rem;
 }
@@ -26,20 +29,28 @@
     box-shadow: 0px 0px 0px 2px $extensions-light;
 }
 
+.alert-spinner {
+    self-align: center;
+}
+
+.icon-section {
+    min-width: 1.25rem;
+    min-height: 1.25rem;
+    display: flex;
+    padding-right: 1rem;
+}
+
 .alert-icon {
-    margin-left: .25rem;
-    margin-right: .25rem;
     vertical-align: middle;
 }
 
 .alert-message {
     color: #555;
     font-weight: bold;
-    font-size: .75rem;
-    line-height: 14px;
+    font-size: .8125rem;
+    line-height: .875rem;
     display: flex;
     align-items: center;
-    padding-left: .5rem;
     padding-right: .5rem;
 }
 
@@ -61,6 +72,7 @@
 
 .alert-connection-button {
     min-height: 2rem;
+    width: 6.5rem;
     padding: 0.55rem 0.9rem;
     border-radius: 0.35rem;
     background: #FF8C1A;
@@ -70,8 +82,9 @@
     border: none;
     cursor: pointer;
     display: flex;
+    justify-content: center;
     align-items: center;
-    align-self: center;
+    align-self: stretch;
     outline-style:none;
 }
 
@@ -82,3 +95,9 @@
 [dir="rtl"] .alert-connection-button {
     margin-left: 13px;
 }
+
+/* prevent last button in list from too much margin to edge of alert */
+.alert-buttons > :last-child {
+    margin-left: 0;
+    margin-right: 0;
+}
diff --git a/src/components/alerts/alert.jsx b/src/components/alerts/alert.jsx
index 4b6bdf493e3a87be40f65f0476d8dfced4ce99bc..db86bd4b8d6dd263ffe3a3b26f27bda62714200e 100644
--- a/src/components/alerts/alert.jsx
+++ b/src/components/alerts/alert.jsx
@@ -34,14 +34,21 @@ const AlertComponent = ({
         className={classNames(styles.alert, styles[level])}
     >
         {/* TODO: implement Rtl handling */}
-        {iconSpinner && (
-            <Spinner className={styles.alertSpinner} />
-        )}
-        {iconURL && (
-            <img
-                className={styles.alertIcon}
-                src={iconURL}
-            />
+        {(iconSpinner || iconURL) && (
+            <div className={styles.iconSection}>
+                {iconSpinner && (
+                    <Spinner
+                        className={styles.alertSpinner}
+                        level={level}
+                    />
+                )}
+                {iconURL && (
+                    <img
+                        className={styles.alertIcon}
+                        src={iconURL}
+                    />
+                )}
+            </div>
         )}
         <div className={styles.alertMessage}>
             {extensionName ? (
diff --git a/src/components/alerts/alerts.css b/src/components/alerts/alerts.css
new file mode 100644
index 0000000000000000000000000000000000000000..3b7cf5221a813058e20205224da0f23fec8d40b6
--- /dev/null
+++ b/src/components/alerts/alerts.css
@@ -0,0 +1,4 @@
+.alerts-inner-container {
+    min-width: 200px;
+    max-width: 548px;
+}
diff --git a/src/components/alerts/alerts.jsx b/src/components/alerts/alerts.jsx
index 21d6c01c45a7960ba64ed1c6f6d414287aab79b8..50acd7ce1619e37df645eefc3cd6914448d934ac 100644
--- a/src/components/alerts/alerts.jsx
+++ b/src/components/alerts/alerts.jsx
@@ -4,6 +4,8 @@ import PropTypes from 'prop-types';
 import Box from '../box/box.jsx';
 import Alert from '../../containers/alert.jsx';
 
+import styles from './alerts.css';
+
 const AlertsComponent = ({
     alertsList,
     className,
@@ -13,24 +15,26 @@ const AlertsComponent = ({
         bounds="parent"
         className={className}
     >
-        {alertsList.map((a, index) => (
-            <Alert
-                closeButton={a.closeButton}
-                content={a.content}
-                extensionId={a.extensionId}
-                extensionName={a.extensionName}
-                iconSpinner={a.iconSpinner}
-                iconURL={a.iconURL}
-                index={index}
-                key={index}
-                level={a.level}
-                message={a.message}
-                showDownload={a.showDownload}
-                showReconnect={a.showReconnect}
-                showSaveNow={a.showSaveNow}
-                onCloseAlert={onCloseAlert}
-            />
-        ))}
+        <Box className={styles.alertsInnerContainer} >
+            {alertsList.map((a, index) => (
+                <Alert
+                    closeButton={a.closeButton}
+                    content={a.content}
+                    extensionId={a.extensionId}
+                    extensionName={a.extensionName}
+                    iconSpinner={a.iconSpinner}
+                    iconURL={a.iconURL}
+                    index={index}
+                    key={index}
+                    level={a.level}
+                    message={a.message}
+                    showDownload={a.showDownload}
+                    showReconnect={a.showReconnect}
+                    showSaveNow={a.showSaveNow}
+                    onCloseAlert={onCloseAlert}
+                />
+            ))}
+        </Box>
     </Box>
 );
 
diff --git a/src/components/alerts/inline-message.jsx b/src/components/alerts/inline-message.jsx
index 8a7330f79716444cfecff2c3f597f5de5d4fbc78..981e1984a1c8531fd579c9f9cad0f4eee537ee86 100644
--- a/src/components/alerts/inline-message.jsx
+++ b/src/components/alerts/inline-message.jsx
@@ -20,6 +20,7 @@ const InlineMessageComponent = ({
             <Spinner
                 small
                 className={styles.spinner}
+                level={'info'}
             />
         )}
         {content}
diff --git a/src/components/backpack/backpack.css b/src/components/backpack/backpack.css
index 6eddfa905c4a6f79eb1017d149b7030e32aa278a..6c3d9fbc2f9bebcfd78d5306a10605641645d406 100644
--- a/src/components/backpack/backpack.css
+++ b/src/components/backpack/backpack.css
@@ -70,6 +70,7 @@
 
 .backpack-item {
     min-width: 4rem;
+    max-width: 6rem;
     margin: 0 0.25rem;
 }
 
diff --git a/src/components/cards/cards.jsx b/src/components/cards/cards.jsx
index 129d2ca5714633b3643708f6ff3c2be962a07037..f137c91a003cd54c4bb053fa172c6eb6a02841f1 100644
--- a/src/components/cards/cards.jsx
+++ b/src/components/cards/cards.jsx
@@ -234,7 +234,11 @@ const Cards = props => {
     if (x === 0 && y === 0) {
         // initialize positions
         x = isRtl ? -292 : 292;
-        y = 365;
+        // The tallest cards are about 385px high, and the default position is pinned
+        // to near the bottom of the blocks palette to allow room to work above.
+        const tallCardHeight = 385;
+        const bottomMargin = 60; // To avoid overlapping the backpack region
+        y = window.innerHeight - tallCardHeight - bottomMargin;
     }
 
     const steps = content[activeDeckId].steps;
diff --git a/src/components/gui/gui.css b/src/components/gui/gui.css
index 1e4785a531bdf15fb15d705d000e28b0bd19947e..888316c3c89389a6f0b6a84978e23cf4649e8ae9 100644
--- a/src/components/gui/gui.css
+++ b/src/components/gui/gui.css
@@ -303,12 +303,10 @@ $fade-out-distance: 15px;
 /* Alerts */
 
 .alerts-container {
-    width: 448px;
-    min-width: 448px;
+    display: flex;
+    justify-content: center;
+    width: 100%;
     z-index: $z-index-alerts;
-    left: 0;
-    right: 0;
-    margin: auto;
     position: absolute;
     margin-top: 53px;
 }
diff --git a/src/components/menu-bar/menu-bar.jsx b/src/components/menu-bar/menu-bar.jsx
index 7e1bf25094cb7ece409093526b0e52496fbeaf9e..d8793b111c865f22dd85c44f126a7310ec0d98ea 100644
--- a/src/components/menu-bar/menu-bar.jsx
+++ b/src/components/menu-bar/menu-bar.jsx
@@ -348,23 +348,25 @@ class MenuBar extends React.Component {
                                         {newProjectMessage}
                                     </MenuItem>
                                 </MenuSection>
-                                <MenuSection>
-                                    {this.props.canSave ? (
-                                        <MenuItem onClick={this.handleClickSave}>
-                                            {saveNowMessage}
-                                        </MenuItem>
-                                    ) : []}
-                                    {this.props.canCreateCopy ? (
-                                        <MenuItem onClick={this.handleClickSaveAsCopy}>
-                                            {createCopyMessage}
-                                        </MenuItem>
-                                    ) : []}
-                                    {this.props.canRemix ? (
-                                        <MenuItem onClick={this.handleClickRemix}>
-                                            {remixMessage}
-                                        </MenuItem>
-                                    ) : []}
-                                </MenuSection>
+                                {(this.props.canSave || this.props.canCreateCopy || this.props.canRemix) && (
+                                    <MenuSection>
+                                        {this.props.canSave ? (
+                                            <MenuItem onClick={this.handleClickSave}>
+                                                {saveNowMessage}
+                                            </MenuItem>
+                                        ) : []}
+                                        {this.props.canCreateCopy ? (
+                                            <MenuItem onClick={this.handleClickSaveAsCopy}>
+                                                {createCopyMessage}
+                                            </MenuItem>
+                                        ) : []}
+                                        {this.props.canRemix ? (
+                                            <MenuItem onClick={this.handleClickRemix}>
+                                                {remixMessage}
+                                            </MenuItem>
+                                        ) : []}
+                                    </MenuSection>
+                                )}
                                 <MenuSection>
                                     <SBFileUploader onUpdateProjectTitle={this.props.onUpdateProjectTitle}>
                                         {(className, renderFileInput, loadProject) => (
diff --git a/src/components/spinner/spinner.css b/src/components/spinner/spinner.css
index a20e79b137150937dba06fb9f13b790cc377627d..3abc8ffbbea117d723b8abe36a98ac5cdb36aa9b 100644
--- a/src/components/spinner/spinner.css
+++ b/src/components/spinner/spinner.css
@@ -1,19 +1,20 @@
 @import "../../css/colors.css";
 
 .spinner {
-    width: 1rem;
-    height: 1rem;
+    width: 1.25rem;
+    height: 1.25rem;
     display: inline-block;
     position: relative;
     border-radius: 50%;
     border-width: .1875rem;
     border-style: solid;
     border-color: $ui-white-transparent;
+    box-sizing: content-box;
 }
 
 .spinner::before, .spinner::after {
-    width: 1rem;
-    height: 1rem;
+    width: 1.25rem;
+    height: 1.25rem;
     content: '';
     border-radius: 50%;
     display: block;
@@ -48,17 +49,25 @@
   }
 }
 
-.spinner.orange {
+.spinner.success {
+    border-color: $extensions-transparent;
+}
+
+.spinner.success::after {
+    border-top-color: $extensions-primary;
+}
+
+.spinner.warn {
     border-color: $error-transparent;
 }
 
-.spinner.orange::after {
+.spinner.warn::after {
     border-top-color: $error-primary;
 }
 
-.spinner.white {
+.spinner.info {
     border-color: $ui-white-transparent;
 }
-.spinner.white::after {
+.spinner.info::after {
     border-top-color: $ui-white;
 }
diff --git a/src/components/spinner/spinner.jsx b/src/components/spinner/spinner.jsx
index bb82fbf51c675e6624902d89ff6caf1ab72b5dde..f25e3ebb18771e9c94a1010930f9d2a65337e92e 100644
--- a/src/components/spinner/spinner.jsx
+++ b/src/components/spinner/spinner.jsx
@@ -7,6 +7,7 @@ import styles from './spinner.css';
 const SpinnerComponent = function (props) {
     const {
         className,
+        level,
         small
     } = props;
     return (
@@ -14,6 +15,7 @@ const SpinnerComponent = function (props) {
             className={classNames(
                 className,
                 styles.spinner,
+                styles[level],
                 {[styles.small]: small}
             )}
         />
@@ -21,9 +23,11 @@ const SpinnerComponent = function (props) {
 };
 SpinnerComponent.propTypes = {
     className: PropTypes.string,
+    level: PropTypes.string,
     small: PropTypes.bool
 };
 SpinnerComponent.defaultProps = {
-    className: ''
+    className: '',
+    level: 'info'
 };
 export default SpinnerComponent;
diff --git a/src/components/sprite-selector/sprite-selector.css b/src/components/sprite-selector/sprite-selector.css
index da89efab0433d86fe091e452f56c06f3fb496e9e..678f61ef49ae2e2d1bf6e99b45637ed67f1800d1 100644
--- a/src/components/sprite-selector/sprite-selector.css
+++ b/src/components/sprite-selector/sprite-selector.css
@@ -31,6 +31,7 @@
     */
     box-sizing: border-box;
     width: calc((100% / $sprites-per-row ) - $space);
+    max-width: 6rem;
     min-width: 4rem;
     min-height: 4rem; /* @todo: calc height same as width */
     margin: calc($space / 2);