1# ArkUI Subsystem Changelog
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3##  cl.arkui.1 Change in Check Rules on the \<Scroll> Component
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5**Access Level**
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7Public
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9**Reason for Change**
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11The [\<Scroll>](../../../application-dev/reference/arkui-ts/ts-container-scroll.md) component supports a single child component. To prevent multiple child components from being added, a check rule is added to the compiler to warn of such attempts.
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13**Change Impact**
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15This change is a non-compatible change. The new check rule does not affect the layout or behavior of the **\<Scroll>** component.
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17**API Level**
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1911
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21**Change Since**
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23OpenHarmony SDK 4.1.3.5
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25**Key API/Component Changes**
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27**\<Scroll>** component
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29**Adaptation Guide**
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31Make sure the **\<Scroll>** component contains only one child component.
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33##  cl.arkui.2 Determination of the Cross Axis Size and stretch Alignment Mode in the \<Flex> Component
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35**Access Level**
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37Public
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39**Reason for Change**
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41In the **\<Flex>** container, the priority of the child component size is higher than that of the **stretch** alignment mode along the cross axis. If both are set, only the cross axis size of the child component takes effect.
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43**Change Impact**
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45This change is a compatible change.
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47API version 9 and earlier versions: If both the child component size and the **stretch** alignment mode are set for the cross axis, the cross axis size of the child component does not take effect.
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49API version 10 and later: If both the child component size and the **stretch** alignment mode are set for the cross axis, the **stretch** alignment mode does not take effect.
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51**Change Since**
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53OpenHarmony SDK 4.1.3.5
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55**Key API/Component Changes**
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57**\<Flex>** component
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59**Adaptation Guide**
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61To make the **stretch** alignment mode for the cross axis take effect, remove the cross axis size settings of the child component.
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